eddystone_radio_users : Messages : 2968-2998 of 3285

Welwyn , that's it, I couldn't remember last night (I'd just got in from a hairy day followed by a 200 mile drive!)

I've got a big tin of Welwyn resistors but they're buried under a great pile of junk (my wife's word!) in the garage but many thanks for the offer Graham. I do have an RS 7W item to hand though so I'll fit it later today,

Cheers,

Jim

From: Graham Adcock <adcock@...>
To: eddystone_radio_users@...
Sent: Thursday, 14 June 2012, 23:53
Subject: Re: [eddystone_radio_users] Re: 680X query

As you say Jim, similar to Zeners.

The green resistors are probably Welwyn - vitreous. Good bits of kit in my opinion. Probably got one if you're stuck...

G'night...

Graham.

----- Original Message -----

From: Jim Jobe

To: eddystone_radio_users@...

Sent: Thursday, June 14, 2012 11:50 PM

Subject: Re: [eddystone_radio_users] Re: 680X query

Cheers Graham. I only placed this query initially because the original resistor looks like a 12W item - one of those green glossy vitreous W...... types,

73,

Jim

From: Graham Adcock <adcock@...>
To: eddystone_radio_users@...
Sent: Thursday, 14 June 2012, 23:42
Subject: Re: [eddystone_radio_users] Re: 680X query

Jim - the 4.5W you've calculated is correct for a 300V HT (300 - 150) x 30mA = 4.5W. This runs the 150V regulator at its maximum current.

However, the 20mA taken by the 2 valves connected to the stabilised supply will come out of that maximum current, reducing the regulator current by 20mA to 10mA but maintaining the 30mA through the dropper resistor and maintaining 4.5W.

At a guess, the original 2k7 indicates a supply nearer 250V. In any case, the 4.5W will be fine in a 7W resistor.

73,

Graham.

----- Original Message -----

From: Jim Jobe

To: eddystone_radio_users@...

Sent: Thursday, June 14, 2012 11:08 PM

Subject: Re: [eddystone_radio_users] Re: 680X query

Hi Roy,

Many thanks for getting back to me - so that should give 4.5W (assuming 300V HT). I think the 2 valves obtaining their HT from the VR150 take about 10mA each though which gives another 3W so 7.5W absolute maximum. I think I'll get away with it then! (At least until I find a 12W resistor!)

Best wishes,

Jim

From: "rkavampsev@..." <rkavampsev@...>
To: eddystone_radio_users@...
Sent: Thursday, 14 June 2012, 9:43
Subject: [eddystone_radio_users] Re: 680X query

Hi JIm

Measure the set ht and you know the vr150/30 draws 30 milliamp max at 150 v so set ht, minus 150 v times 30 milliamp equals wattage of dropping resistor

hope that helps jim

cheers roy

GM4VKI

#2969

From: Jim Jobe <jimjobe1@...>
Date: Fri Jun 15, 2012 1:03 pm
Subject: Re: Re: 680X query

jimjobe1

I've connected up the new resistor and it's drawing 47mA which makes just under 6W dissipation. I was surprised at how hot it runs though (having burnt my finger on it). 6W doesn't sound much but it's a tenth of a table lamp's 60W bulb dissipation after all. I'll fit a replacement 12W item when I unearth my tin! I've had spinal surgery recently and am banned from rummaging in the tip.i.e.garage by SWMBO!Thanks everyone,

Jim

#2970

From: rkavampsev@...
Date: Fri Jun 15, 2012 1:13 pm
Subject: Re: Re: 680X query

merlinrail

Hi Jim

Something wrong here

If its drawing 47 ma then the stabaliser valve isnt within its working capacity

Pull out the two valves that the stabaliser is for and see what the vr150/30 draws itself .

i suspect you have a faulty cct about one of the valves that the VR150 is designed to stabalised .

cheers roy

GM4VKI

#2971

From: Jim Jobe <jimjobe1@...>
Date: Fri Jun 15, 2012 3:14 pm
Subject: Re: Re: 680X query

jimjobe1

Is 47mA not a bit high, considering 40mA is the absolute max for the VR150? I know that less than this actually flows through it under normal conditions but under fault conditions it could receive the whole lot. I'm surprised that Eddystone didn't make R66 higher which they could easily have done and still had enough current for the HF oscillator, BFO and mixer anode. I had a sudden thought that the previous owner might have had the mains transformer set to 200V accidentally but that isn't the case. Still the HT Voltage does seem a bit high at 275V.

I found a stray wire in the BFO compartment which had come undone from the earth tag on the BFO transformer. At first glance it seems to be earthing some front panel controls, but these are already earthed elsewhere. Anyway I've reconnected it and it doesn't make any difference to the working. A bit of redundancy, I suppose.

One thing, there's nothing like a bit of fault finding to help you get to know your set!

Jim

From: Jim Jobe <jimjobe1@...>
To: "eddystone_radio_users@..." <eddystone_radio_users@...>
Sent: Friday, 15 June 2012, 14:03
Subject: Re: [eddystone_radio_users] Re: 680X query

Jim

#2972

From: Jim Jobe <jimjobe1@...>
Date: Fri Jun 15, 2012 3:54 pm
Subject: Re: Re: 680X query

jimjobe1

I've already though of that Roy but I think it's the 275V that is causing the high current, but that seems to be within spec as Eddystone quote 260V +-5% in the handbook (using a 1000ohm/Volt meter, not that that would make a difference in this case)

I tried pulling the HF Osc (EF91) and Mixer/Osc (6BE6) valves and that caused no change in the PD across R66 which was 122V. Interestingly, with all valves inserted and BFO off, this PD varies between 122V quiescent and 138V with RF pot turned fully down. Some valve(s) presumably increase their Ia with increasing signal input.

I might try increasing R66 in value when I find my stock of wirewounds.

Best wishes,

Jim

From: "rkavampsev@..." <rkavampsev@...>
To: eddystone_radio_users@...
Sent: Friday, 15 June 2012, 14:13
Subject: Re: [eddystone_radio_users] Re: 680X query

Hi Jim

Something wrong here

If its drawing 47 ma then the stabaliser valve isnt within its working capacity

Pull out the two valves that the stabaliser is for and see what the vr150/30 draws itself .

i suspect you have a faulty cct about one of the valves that the VR150 is designed to stabalised .

cheers roy

GM4VKI

#2973

From: Jim Jobe <jimjobe1@...>
Date: Fri Jun 15, 2012 3:57 pm
Subject: Re: Re: 680X query

jimjobe1

PS; Your attachment was blocked by Yahoo.It seems the group isn't set up to receive attachments. Can you send it direct to me please?

Jim

From: "rkavampsev@..." <rkavampsev@...>
To: eddystone_radio_users@...
Sent: Friday, 15 June 2012, 14:13
Subject: Re: [eddystone_radio_users] Re: 680X query

Hi Jim

Something wrong here

If its drawing 47 ma then the stabaliser valve isnt within its working capacity

Pull out the two valves that the stabaliser is for and see what the vr150/30 draws itself .

i suspect you have a faulty cct about one of the valves that the VR150 is designed to stabalised .

cheers roy

GM4VKI

#2974

From: BenG4BXD <Military1944@...>
Date: Fri Jun 15, 2012 4:30 pm
Subject: Re: Re: 680X query

militaryoper...

Some valve(s) presumably increase their Ia with increasing signal input.
------------

if not all?

#2975

From: Jim Jobe <jimjobe1@...>
Date: Fri Jun 15, 2012 5:27 pm
Subject: Re: Re: 680X query

jimjobe1

That's right Ben. It's interesting to see what a big effect that has on the HT voltage,

jim

From: BenG4BXD <Military1944@...>
To: eddystone_radio_users@...
Sent: Friday, 15 June 2012, 17:30
Subject: Re: [eddystone_radio_users] Re: 680X query

Some valve(s) presumably increase their Ia with increasing signal input.
------------

if not all?

#2976

From: Jim Jobe <jimjobe1@...>
Date: Fri Jun 15, 2012 6:31 pm
Subject: Re: Re: 680X query

jimjobe1

The plot thickens! I've just measured the HT voltage again (DMM) and, with the Archers tuned in on R4 MW, I'm getting 300V at the rectifier side of the choke and 283V on the other side of it. The 265V quoted by Eddystone in the handbook is for the rectifier side and isn't, as I thought, the main HT line voltage which should be about 220V with a 1000 ohm/Volt meter.

This means that the transformer output is way too high by 60-70V. It seems to be the original Eddystone component and the input is set to the 230V position so I'm totally at a loss now as to why this should be so high.

Any suggestions gratefully received! This set seems to have the same jinx as my computer - it develops faults that no-one else has ever heard of! I only bought the set last year and haven't used it much. but I've long suspected its performance isn't up to scratch.

Jim

#2977

From: rkavampsev@...
Date: Fri Jun 15, 2012 6:35 pm
Subject: Re: Re: 680X query

merlinrail

Jim Measure the AC going into the set off the mains

My mains here is 256 volts instead of 230-240 which its supposed to be

cheers roy

Gm4VKI

#2978

From: Jim Jobe <jimjobe1@...>
Date: Fri Jun 15, 2012 7:00 pm
Subject: Re: Re: 680X query

jimjobe1

That's an idea Roy, I'll try that in a mo,

Jim

From: "rkavampsev@..." <rkavampsev@...>
To: eddystone_radio_users@...
Sent: Friday, 15 June 2012, 19:35
Subject: Re: [eddystone_radio_users] Re: 680X query

Jim Measure the AC going into the set off the mains

My mains here is 256 volts instead of 230-240 which its supposed to be

cheers roy

Gm4VKI

#2979

From: Jim Jobe <jimjobe1@...>
Date: Fri Jun 15, 2012 10:33 pm
Subject: Re: Re: 680X query

jimjobe1

It's 244V Roy, not enough I'm afraid!

Jim

From: Jim Jobe <jimjobe1@...>
To: "eddystone_radio_users@..." <eddystone_radio_users@...>
Sent: Friday, 15 June 2012, 20:00
Subject: Re: [eddystone_radio_users] Re: 680X query

That's an idea Roy, I'll try that in a mo,

Jim

From: "rkavampsev@..." <rkavampsev@...>
To: eddystone_radio_users@...
Sent: Friday, 15 June 2012, 19:35
Subject: Re: [eddystone_radio_users] Re: 680X query

Jim Measure the AC going into the set off the mains

My mains here is 256 volts instead of 230-240 which its supposed to be

cheers roy

Gm4VKI

#2980

From: "Gerry O'Hara" <gerryohara@...>
Date: Sat Jun 16, 2012 2:55 pm
Subject: RE: Re: 680X query

g8guh

Hi Jim,

I note that you are checking voltages with a DMM – as you imply in the discussion, these instruments (even the cheapest ones) have a high Ohms per volt (‘o.p.v’) – usually tens of mohms, similar to a valve voltmeter (VTVM). The voltage table in the 680X manual provides nodal voltages using typical moving coil multimeters used ‘in the day’ with much lower o.p.v.: a ‘Weston’ and ‘AVO’ (note that the model of ‘AVO’ quoted is not a Model 8, and has an even lower o.p.v. than the ‘Weston, which is noted as only 1000 o.p.v.). I note that you make reference to this effect when discussing voltages you measure in the 680X circuit and, implicitly, this is especially the case in higher-impedance circuits (and as such a DMM will often read voltages significantly higher than in the 680X voltage table). In order to check against the figures in the table, you can easily simulate a lower o.p.v. meter for DC voltage ranges by placing a suitable resistor in parallel with the test leads, eg. on a 250v meter range, use a 250kohm resistor to simulate a 1000 o.p.v. meter sensitivity. Also, when making voltage measurements make sure the control settings are as stated in the table preamble – shorting the aerial, and settings for the RF gain and AGC in particular.

Your mains voltage is 6% higher than the 230vAC of the primary winding on the transformer. This would translate to 260vAC on one half of the secondary HT winding. Also, note that there is a 5% tolerance on voltages provided in the table, so this could be as high as 257vAC and still be (just) within tolerance – very close to the 260v to be expected from your 244vAC mains voltage. Have you measured the AC voltage across the 5Z4G anodes (should be between 520vAC given your mains voltage (type of meter will not make much difference here). If this is much higher, say by 5%, there may be a problem with the transformer, though a higher secondary voltage would be very unusual – maybe a partially shorted primary could cause this effect, but I have never come across that.

Gerry

From: eddystone_radio_users@... [mailto:eddystone_radio_users@...] On Behalf Of Jim Jobe
Sent: June-15-12 8:55 AM
To: eddystone_radio_users@...
Subject: Re: [eddystone_radio_users] Re: 680X query

I might try increasing R66 in value when I find my stock of wirewounds.

Best wishes,

Jim

From: "rkavampsev@..." <rkavampsev@...>
To: eddystone_radio_users@...
Sent: Friday, 15 June 2012, 14:13
Subject: Re: [eddystone_radio_users] Re: 680X query

Hi Jim

Something wrong here

If its drawing 47 ma then the stabaliser valve isnt within its working capacity

Pull out the two valves that the stabaliser is for and see what the vr150/30 draws itself .

i suspect you have a faulty cct about one of the valves that the VR150 is designed to stabalised .

cheers roy

GM4VKI

#2981

From: Jim Jobe <jimjobe1@...>
Date: Sat Jun 16, 2012 3:44 pm
Subject: Re: Re: 680X query

jimjobe1

Hi Gerry,

I take on board all you've said. That's a useful tip on how to simulate a low impedance meter and I'll try that for comparison purposes. I've been using a DMM and also an AVO8 (see above for latest measurements as compared with another chap's set). When all's said and done though there is still that high current (47mA) through R66, measured with a series milliammeter, which is what alerted me in the first place and probably caused the original R66 to burn out, as well as, possibly, C115. I'll keep everyone in touch with what develops,

best wishes,

Jim

Quote:

Originally Posted by g4aaw pete

As promised, measured on Fluke 87

a/c input = 244v a/c
a/c o/p from transformer from ' 0' terminal to ' 250 ' terminal = 271v a/c
Chassis to rectifier side of choke = 262v d.c.
Other side of choke = 249v d.c.

Hope that's useful.

Regards
Pete

Cheers Pete,

My measurements for transformer using AVO8:

i/p: 244VAC

o/p: 266VAC

6.3V 3A winding: 6.6VAC

Chassis to rectifier side of choke: 300VDC

Other side of choke: 283VDC

So, my output to the rectifier is actually lower than yours Pete, yet the final DC HT is considerably higher. What on earth is happening?
Jim

I've just had a thought: there's another 40uF capacitor wired across the original by a previous owner. I've assumed this is because the original is duff but what would happen if it wasn't? I would then have the equivalent of an 80uF smoothing capacitor - would this cause a rise in HT voltage?

Last edited by jim_jobe; Today at 01:51 PM.

From: Gerry O'Hara <gerryohara@...>
To: eddystone_radio_users@...
Sent: Saturday, 16 June 2012, 15:55
Subject: RE: [eddystone_radio_users] Re: 680X query

Hi Jim,

Gerry

I might try increasing R66 in value when I find my stock of wirewounds.

Best wishes,

Jim

From: "rkavampsev@..." <rkavampsev@...>
To: eddystone_radio_users@...
Sent: Friday, 15 June 2012, 14:13
Subject: Re: [eddystone_radio_users] Re: 680X query

Hi Jim

Something wrong here

If its drawing 47 ma then the stabaliser valve isnt within its working capacity

Pull out the two valves that the stabaliser is for and see what the vr150/30 draws itself .

i suspect you have a faulty cct about one of the valves that the VR150 is designed to stabalised .

cheers roy

GM4VKI

#2982

From: "Gerry O'Hara" <gerryohara@...>
Date: Sat Jun 16, 2012 5:33 pm
Subject: RE: Re: 680X query

g8guh

Hi Jim,

Yes, there is still that original issue and as I think Roy noted, most likely a component problem on the circuits supplied by the stabilizer (have you tried changing the stabilizer by the way? – perhaps it is faulty).

Gerry

From: eddystone_radio_users@... [mailto:eddystone_radio_users@...] On Behalf Of Jim Jobe
Sent: June-16-12 8:44 AM
To: eddystone_radio_users@...
Subject: Re: [eddystone_radio_users] Re: 680X query

Hi Gerry,

best wishes,

Jim

Quote:

Originally Posted by g4aaw pete

Last edited by jim_jobe; Today at 01:51 PM.

jim_jobe is online now

From: Gerry O'Hara <gerryohara@...>
To: eddystone_radio_users@...
Sent: Saturday, 16 June 2012, 15:55
Subject: RE: [eddystone_radio_users] Re: 680X query

Hi Jim,

Gerry

I might try increasing R66 in value when I find my stock of wirewounds.

Best wishes,

Jim

From: "rkavampsev@..." <rkavampsev@...>
To: eddystone_radio_users@...
Sent: Friday, 15 June 2012, 14:13
Subject: Re: [eddystone_radio_users] Re: 680X query

Hi Jim

Something wrong here

If its drawing 47 ma then the stabaliser valve isnt within its working capacity

Pull out the two valves that the stabaliser is for and see what the vr150/30 draws itself .

i suspect you have a faulty cct about one of the valves that the VR150 is designed to stabalised .

cheers roy

GM4VKI

#2983

From: "Jim McGowan" <jimm0mac@...>
Date: Sat Jun 16, 2012 6:29 pm
Subject: Re: Re: 680X query

jim245185

Hi Gerry , on another subject , regarding the AFseries of transistors does Tor say that the biasing resistors need changing to different values if AF types are fitted in lieu ?

Regards .

Jim M0MAC

----- Original Message -----

From: Gerry O'Hara

To: eddystone_radio_users@...

Sent: Saturday, June 16, 2012 6:33 PM

Subject: RE: [eddystone_radio_users] Re: 680X query

Hi Jim,

Yes, there is still that original issue and as I think Roy noted, most likely a component problem on the circuits supplied by the stabilizer (have you tried changing the stabilizer by the way? – perhaps it is faulty).

Gerry

From: eddystone_radio_users@... [mailto:eddystone_radio_users@...] On Behalf Of Jim Jobe
Sent: June-16-12 8:44 AM
To: eddystone_radio_users@...
Subject: Re: [eddystone_radio_users] Re: 680X query

Hi Gerry,

I take on board all you've said. That's a useful tip on how to simulate a low impedance meter and I'll try that for comparison purposes. I've been using a DMM and also an AVO8 (see above for latest measurements as compared with another chap's set). When all's said and done though there is still that high current (47mA) through R66, measured with a series milliammeter, which is what alerted me in the first place and probably caused the original R66 to burn out, as well as, possibly, C115. I'll keep everyone in touch with what develops,

best wishes,

Jim

Quote:

Originally Posted by g4aaw pete

As promised, measured on Fluke 87

a/c input = 244v a/c
a/c o/p from transformer from ' 0' terminal to ' 250 ' terminal = 271v a/c
Chassis to rectifier side of choke = 262v d.c.
Other side of choke = 249v d.c.

Hope that's useful.

Regards
Pete

Cheers Pete,

My measurements for transformer using AVO8:

i/p: 244VAC

o/p: 266VAC

6.3V 3A winding: 6.6VAC

Chassis to rectifier side of choke: 300VDC

Other side of choke: 283VDC

So, my output to the rectifier is actually lower than yours Pete, yet the final DC HT is considerably higher. What on earth is happening?
Jim

I've just had a thought: there's another 40uF capacitor wired across the original by a previous owner. I've assumed this is because the original is duff but what would happen if it wasn't? I would then have the equivalent of an 80uF smoothing capacitor - would this cause a rise in HT voltage?

Last edited by jim_jobe; Today at 01:51 PM.

From: Gerry O'Hara <gerryohara@...>
To: eddystone_radio_users@...
Sent: Saturday, 16 June 2012, 15:55
Subject: RE: [eddystone_radio_users] Re: 680X query

Hi Jim,

I note that you are checking voltages with a DMM – as you imply in the discussion, these instruments (even the cheapest ones) have a high Ohms per volt (‘o.p.v’) – usually tens of mohms, similar to a valve voltmeter (VTVM). The voltage table in the 680X manual provides nodal voltages using typical moving coil multimeters used ‘in the day’ with much lower o.p.v.: a ‘Weston’ and ‘AVO’ (note that the model of ‘AVO’ quoted is not a Model 8, and has an even lower o.p.v. than the ‘Weston, which is noted as only 1000 o.p.v.). I note that you make reference to this effect when discussing voltages you measure in the 680X circuit and, implicitly, this is especially the case in higher-impedance circuits (and as such a DMM will often read voltages significantly higher than in the 680X voltage table). In order to check against the figures in the table, you can easily simulate a lower o.p.v. meter for DC voltage ranges by placing a suitable resistor in parallel with the test leads, eg. on a 250v meter range, use a 250kohm resistor to simulate a 1000 o.p.v. meter sensitivity. Also, when making voltage measurements make sure the control settings are as stated in the table preamble – shorting the aerial, and settings for the RF gain and AGC in particular.

Your mains voltage is 6% higher than the 230vAC of the primary winding on the transformer. This would translate to 260vAC on one half of the secondary HT winding. Also, note that there is a 5% tolerance on voltages provided in the table, so this could be as high as 257vAC and still be (just) within tolerance – very close to the 260v to be expected from your 244vAC mains voltage. Have you measured the AC voltage across the 5Z4G anodes (should be between 520vAC given your mains voltage (type of meter will not make much difference here). If this is much higher, say by 5%, there may be a problem with the transformer, though a higher secondary voltage would be very unusual – maybe a partially shorted primary could cause this effect, but I have never come across that.

Gerry

From: eddystone_radio_users@... [mailto:eddystone_radio_users@...] On Behalf Of Jim Jobe
Sent: June-15-12 8:55 AM
To: eddystone_radio_users@...
Subject: Re: [eddystone_radio_users] Re: 680X query

I've already though of that Roy but I think it's the 275V that is causing the high current, but that seems to be within spec as Eddystone quote 260V +-5% in the handbook (using a 1000ohm/Volt meter, not that that would make a difference in this case)

I tried pulling the HF Osc (EF91) and Mixer/Osc (6BE6) valves and that caused no change in the PD across R66 which was 122V. Interestingly, with all valves inserted and BFO off, this PD varies between 122V quiescent and 138V with RF pot turned fully down. Some valve(s) presumably increase their Ia with increasing signal input.

I might try increasing R66 in value when I find my stock of wirewounds.

Best wishes,

Jim

From: "rkavampsev@..." <rkavampsev@...>
To: eddystone_radio_users@...
Sent: Friday, 15 June 2012, 14:13
Subject: Re: [eddystone_radio_users] Re: 680X query

Hi Jim

Something wrong here

If its drawing 47 ma then the stabaliser valve isnt within its working capacity

Pull out the two valves that the stabaliser is for and see what the vr150/30 draws itself .

i suspect you have a faulty cct about one of the valves that the VR150 is designed to stabalised .

cheers roy

GM4VKI

#2984

From: "tor_marthinsen" <tor_marthinsen@...>
Date: Sat Jun 16, 2012 6:37 pm
Subject: Voltages in a 680X

tor_marthinsen

Hi Jim,
I've with interest read about your problems with your 680X. You say that the
current through R66 is 47mA, I assume that the voltage at point F- is 150Volts.
The VR150/30 supplies three valves, the current taken in the BFO equals 6-7mA,
in the oscillator 4-5mA and the frequency changer about 12mA - all together
about 23mA. The regulator valve can take a maximum of 40mA, so that the current
in R66 might have been maximum 63mA, much lower than your 47mA. However 47mA in
2.7kOhms is 127Volts, add 150Volts from the regulator and your HT+ equals
277Volts - this is much above the value given in the handbook, 225Volts.
You mention that the input voltage is 244Volts AC, this is 6% higher than the
set needs. This means that the voltage at E- also is higher by 6%, perhaps
260Volts AC. If the 'Standby' switch is off then the receiver draws no current
and the capacitors C114 and C115 gets the full peak voltage - more than
360Volts, which is too much for C115.
I suggest you put a resistor in series with your AC-input to reduce the input
voltage to 230Volts AC or a little below - 100-200Ohms ought to do the trick.
Then when your input voltage is correct you can measure all the voltage points
in the diagram to find where your real problems are!
Good luck! Tor

#2985

From: Jim Jobe <jimjobe1@...>
Date: Sat Jun 16, 2012 9:20 pm
Subject: Re: Voltages in a 680X

jimjobe1

Many thanks Tor. I actually measured the current through R66 by detaching one of its leads and inserting a millivoltmeter in series. I'll put a resistor in series with the supply as you say - I have a selection of different light bulbs which I'll try first but I wish I still had the Variac or one of the large rheostats I used to use when teaching!

Best wishes,

Jim

From: tor_marthinsen <tor_marthinsen@...>
To: eddystone_radio_users@...
Sent: Saturday, 16 June 2012, 19:37
Subject: [eddystone_radio_users] Voltages in a 680X

Hi Jim,
I've with interest read about your problems with your 680X. You say that the current through R66 is 47mA, I assume that the voltage at point F- is 150Volts. The VR150/30 supplies three valves, the current taken in the BFO equals 6-7mA, in the oscillator 4-5mA and the frequency changer about 12mA - all together about 23mA. The regulator valve can take a maximum of 40mA, so that the current in R66 might have been maximum 63mA, much lower than your 47mA. However 47mA in 2.7kOhms is 127Volts, add 150Volts from the regulator and your HT+ equals 277Volts - this is much above the value given in the handbook, 225Volts.
You mention that the input voltage is 244Volts AC, this is 6% higher than the set needs. This means that the voltage at E- also is higher by 6%, perhaps 260Volts AC. If the 'Standby' switch is off then the receiver draws no current and the capacitors C114 and C115 gets the full peak voltage - more than 360Volts, which is too much for C115.
I suggest you put a resistor in series with your AC-input to reduce the input voltage to 230Volts AC or a little below - 100-200Ohms ought to do the trick. Then when your input voltage is correct you can measure all the voltage points in the diagram to find where your real problems are!
Good luck! Tor

#2986

From: Jim Jobe <jimjobe1@...>
Date: Sat Jun 16, 2012 9:29 pm
Subject: Re: Re: 680X query

jimjobe1

First thing I did Gerry and I also pulled the Oscillator, BFO and Mixer valves with no change in current drawn. The Stabiliser anode is at 151V so the excess current (measured directly) is caused purely by the enhanced HT Voltage. I'll try changing the rectifier as well tomorrow and completely replace the reservoir and smoothing capacitors, not just rely on bridging them with new components. There's one thing about obscure faults; they sure are interesting and get the old grey cells working! When I get time I intend going right through the set, checking all the capacitors and resistors as well,

Many thanks for your interest,

Jim

From: Gerry O'Hara <gerryohara@...>
To: eddystone_radio_users@...
Sent: Saturday, 16 June 2012, 18:33
Subject: RE: [eddystone_radio_users] Re: 680X query

Hi Jim,

Gerry

Hi Gerry,

best wishes,

Jim

Quote:

Originally Posted by g4aaw pete

Last edited by jim_jobe; Today at 01:51 PM.

From: Gerry O'Hara <gerryohara@...>
To: eddystone_radio_users@...
Sent: Saturday, 16 June 2012, 15:55
Subject: RE: [eddystone_radio_users] Re: 680X query

Hi Jim,

Gerry

I might try increasing R66 in value when I find my stock of wirewounds.

Best wishes,

Jim

From: "rkavampsev@..." <rkavampsev@...>
To: eddystone_radio_users@...
Sent: Friday, 15 June 2012, 14:13
Subject: Re: [eddystone_radio_users] Re: 680X query

Hi Jim

Something wrong here

If its drawing 47 ma then the stabaliser valve isnt within its working capacity

Pull out the two valves that the stabaliser is for and see what the vr150/30 draws itself .

i suspect you have a faulty cct about one of the valves that the VR150 is designed to stabalised .

cheers roy

GM4VKI

#2987

From: Jim Jobe <jimjobe1@...>
Date: Sun Jun 17, 2012 4:48 pm
Subject: Re: Re: 680X query

jimjobe1

I've connected 2X22ohm and a 33ohm resistor temporarily in series with the mains input and got the voltages down more or less where they should be. I've also fitted new reservoir and smoothing capacitors. However, listening to some music on MW the audio sounds pretty awful. I know it's not a HiFi set but a push-pull amplifier as the output should sound better than this does. So, next task is to have a look at the output stage, although it might be more sensible to check all the coupling capacitors first.
Jim

#2988

From: "Gerry O'Hara" <gerryohara@...>
Date: Sun Jun 17, 2012 9:44 pm
Subject: RE: Re: 680X query

g8guh

No, I believe they are direct substitutes.

Gerry

From: eddystone_radio_users@... [mailto:eddystone_radio_users@...] On Behalf Of Jim McGowan
Sent: June-16-12 11:30 AM
To: eddystone_radio_users@...
Subject: Re: [eddystone_radio_users] Re: 680X query

Hi Gerry , on another subject , regarding the AFseries of transistors does Tor say that the biasing resistors need changing to different values if AF types are fitted in lieu ?

Regards .

Jim M0MAC

----- Original Message -----
From: Gerry O'Hara
To: eddystone_radio_users@...
Sent: Saturday, June 16, 2012 6:33 PM
Subject: RE: [eddystone_radio_users] Re: 680X query

Hi Jim,
Yes, there is still that original issue and as I think Roy noted, most likely a component problem on the circuits supplied by the stabilizer (have you tried changing the stabilizer by the way? – perhaps it is faulty).
Gerry
From: eddystone_radio_users@... [mailto:eddystone_radio_users@...] On Behalf Of Jim Jobe
Sent: June-16-12 8:44 AM
To: eddystone_radio_users@...
Subject: Re: [eddystone_radio_users] Re: 680X query

Hi Gerry,
I take on board all you've said. That's a useful tip on how to simulate a low impedance meter and I'll try that for comparison purposes. I've been using a DMM and also an AVO8 (see above for latest measurements as compared with another chap's set). When all's said and done though there is still that high current (47mA) through R66, measured with a series milliammeter, which is what alerted me in the first place and probably caused the original R66 to burn out, as well as, possibly, C115. I'll keep everyone in touch with what develops,
best wishes,
Jim
Quote:
Originally Posted by g4aaw pete
As promised, measured on Fluke 87

a/c input = 244v a/c
a/c o/p from transformer from ' 0' terminal to ' 250 ' terminal = 271v a/c
Chassis to rectifier side of choke = 262v d.c.
Other side of choke = 249v d.c.

Hope that's useful.

Regards
Pete
Cheers Pete,

My measurements for transformer using AVO8:

i/p: 244VAC

o/p: 266VAC

6.3V 3A winding: 6.6VAC

Chassis to rectifier side of choke: 300VDC

Other side of choke: 283VDC

So, my output to the rectifier is actually lower than yours Pete, yet the final DC HT is considerably higher. What on earth is happening?
Jim

I've just had a thought: there's another 40uF capacitor wired across the original by a previous owner. I've assumed this is because the original is duff but what would happen if it wasn't? I would then have the equivalent of an 80uF smoothing capacitor - would this cause a rise in HT voltage?
Last edited by jim_jobe; Today at 01:51 PM.

From: Gerry O'Hara <gerryohara@...>
To: eddystone_radio_users@...
Sent: Saturday, 16 June 2012, 15:55
Subject: RE: [eddystone_radio_users] Re: 680X query

Hi Jim,
I note that you are checking voltages with a DMM – as you imply in the discussion, these instruments (even the cheapest ones) have a high Ohms per volt (‘o.p.v’) – usually tens of mohms, similar to a valve voltmeter (VTVM). The voltage table in the 680X manual provides nodal voltages using typical moving coil multimeters used ‘in the day’ with much lower o.p.v.: a ‘Weston’ and ‘AVO’ (note that the model of ‘AVO’ quoted is not a Model 8, and has an even lower o.p.v. than the ‘Weston, which is noted as only 1000 o.p.v.). I note that you make reference to this effect when discussing voltages you measure in the 680X circuit and, implicitly, this is especially the case in higher-impedance circuits (and as such a DMM will often read voltages significantly higher than in the 680X voltage table). In order to check against the figures in the table, you can easily simulate a lower o.p.v. meter for DC voltage ranges by placing a suitable resistor in parallel with the test leads, eg. on a 250v meter range, use a 250kohm resistor to simulate a 1000 o.p.v. meter sensitivity. Also, when making voltage measurements make sure the control settings are as stated in the table preamble – shorting the aerial, and settings for the RF gain and AGC in particular.
Your mains voltage is 6% higher than the 230vAC of the primary winding on the transformer. This would translate to 260vAC on one half of the secondary HT winding. Also, note that there is a 5% tolerance on voltages provided in the table, so this could be as high as 257vAC and still be (just) within tolerance – very close to the 260v to be expected from your 244vAC mains voltage. Have you measured the AC voltage across the 5Z4G anodes (should be between 520vAC given your mains voltage (type of meter will not make much difference here). If this is much higher, say by 5%, there may be a problem with the transformer, though a higher secondary voltage would be very unusual – maybe a partially shorted primary could cause this effect, but I have never come across that.
Gerry
From: eddystone_radio_users@... [mailto:eddystone_radio_users@...] On Behalf Of Jim Jobe
Sent: June-15-12 8:55 AM
To: eddystone_radio_users@...
Subject: Re: [eddystone_radio_users] Re: 680X query

I've already though of that Roy but I think it's the 275V that is causing the high current, but that seems to be within spec as Eddystone quote 260V +-5% in the handbook (using a 1000ohm/Volt meter, not that that would make a difference in this case)
I tried pulling the HF Osc (EF91) and Mixer/Osc (6BE6) valves and that caused no change in the PD across R66 which was 122V. Interestingly, with all valves inserted and BFO off, this PD varies between 122V quiescent and 138V with RF pot turned fully down. Some valve(s) presumably increase their Ia with increasing signal input.
I might try increasing R66 in value when I find my stock of wirewounds.
Best wishes,
Jim
From: "rkavampsev@..." <rkavampsev@...>
To: eddystone_radio_users@...
Sent: Friday, 15 June 2012, 14:13
Subject: Re: [eddystone_radio_users] Re: 680X query

Hi Jim
Something wrong here
If its drawing 47 ma then the stabaliser valve isnt within its working capacity
Pull out the two valves that the stabaliser is for and see what the vr150/30 draws itself .
i suspect you have a faulty cct about one of the valves that the VR150 is designed to stabalised .
cheers roy
GM4VKI

#2990

From: "py2lsb" <py2lsb@...>
Date: Wed Jun 20, 2012 2:31 am
Subject: Eddystone S680X

py2lsb

Greetings friends of the group.

Today is a happy day for me, found in Brazil S680x Eddystone in a reasonable
state of repair and working very well.

As I said before, a radio is very rare in Brazil and I'm happy to be able to
afford.

The only problem is that this is not the center of the dial and the dial lamps
do not exist, but it is easy to get them.

I will photograph and put on my blog if anyone wants to take a look to make a
visit and leave a comment and I'll be very grateful.

Thanks to friends Gerry O'Hara, Andrew Kersey and all others who tried to help
me find an Eddystone al in the UK.

I'm reading the matter of Mr. Gerry O'Hara on the restoration of a S680X a
museum and I am finding it very nice.

Have not given up the idea of buying a radio directly from the UK,
but because of the high cost of shipping will wait a little longer to get
another radio.

Thank you, and for those who want to take a quick glance at Eddystone S680x I
bought here in Brazil, follow the link below. 73 all.

http://www.py2lsb.blogspot.com.br/2012/06/eddystone-s680x.html


PY2LSB - Ricardo
Aparecida City - GG77JE -
Brasil.

Reply | Messages in this Topic (1)

#2991

From: BenG4BXD <Military1944@...>
Date: Sun Jun 24, 2012 3:08 pm
Subject: HV PSU. PS-510 psu, used with Trio TS-510 hf rig.

militaryoper...

PS-510 psu, used with Trio TS-510 hf rig. Looks un-molested. Gives 800,
300, 150, 12.6, 6.3v.

Heavy so post costs a bit. Anyway, psu £35.

pics:
http://www.vintage-radio.net/forum/attachment.php?attachmentid=67973&d=134048473\
1
http://www.vintage-radio.net/forum/attachment.php?attachmentid=67974&d=134048473\
1

Ben.

#2992

From: Keith Evans <g3vkw@...>
Date: Sun Jun 24, 2012 6:39 pm
Subject: Re: HV PSU. PS-510 psu, used with Trio TS-510 hf rig.

g3vkw

Hello Ben,

If you have not had any one else offer to buy it, I would like to.

Keith G3VKW

----- Original Message -----

From: BenG4BXD

To: b2spy@...

Cc: spyradiosets@yahoogroups.com ; euro_ba_swap@yahoogroups.com ; eddystone_radio_users@...

Sent: Sunday, June 24, 2012 4:08 PM

Subject: [eddystone_radio_users] HV PSU. PS-510 psu, used with Trio TS-510 hf rig.

PS-510 psu, used with Trio TS-510 hf rig. Looks un-molested. Gives 800,
300, 150, 12.6, 6.3v.

Heavy so post costs a bit. Anyway, psu £35.

pics:
http://www.vintage-radio.net/forum/attachment.php?attachmentid=67973&d=1340484731
http://www.vintage-radio.net/forum/attachment.php?attachmentid=67974&d=1340484731

Ben.

#2993

From: "vk5abc" <vk5abc@...>
Date: Mon Jun 25, 2012 2:33 pm
Subject: Newbie

vk5abc

Hello All
I have just joined and am seeking help, as I just just purchased a 1995/2
receiver. It has the failed bite test however I don't have a service manual. I
don't have a circuit either. Can someone point me in the right direction. BTW
the battery on the cpu board what is it? is it the same as the 1650. One other
thing on the brochure it mentioned a 1161 panoramic display, anyone seen one? I
gather these are as rare as hens teeth.

73's Lee

#2994

From: "casy_ch@..." <casy_ch@...>
Date: Mon Jun 25, 2012 2:48 pm
Subject: Re: Newbie

casy_ch

Hello Lee

Eventually Telford Electronics (www.telford-electronics.com) would have some doc. Ask them.

Racal used to sell the Eddystone 1161 panoramic adapter under their brand as Racal RA-1766 which I have. Inside it is all labelled Eddystone.

73 de Jean-Claude, HB3YDH

Am 25.06.2012 16:33, schrieb vk5abc:

Hello All
I have just joined and am seeking help, as I just just purchased a 1995/2 receiver. It has the failed bite test however I don't have a service manual. I don't have a circuit either. Can someone point me in the right direction. BTW the battery on the cpu board what is it? is it the same as the 1650. One other thing on the brochure it mentioned a 1161 panoramic display, anyone seen one? I gather these are as rare as hens teeth.

73's Lee

-- Vy 73 de Jean-Claude, HB3YDH

#2995

From: "L D Ritta" <vk5abc@...>
Date: Mon Jun 25, 2012 2:55 pm
Subject: RE: Newbie

vk5abc

Hello Jean-Claude

Do you have a photo and do you have a manual for the Racal RA-1766.

73’s Lee VK5ABC

From: eddystone_radio_users@... [mailto:eddystone_radio_users@...] On Behalf Of casy_ch@...
Sent: Tuesday, 26 June 2012 12:19 AM
To: eddystone_radio_users@...
Subject: Re: [eddystone_radio_users] Newbie

Am 25.06.2012 16:33, schrieb vk5abc:

Hello All
I have just joined and am seeking help, as I just just purchased a 1995/2 receiver. It has the failed bite test however I don't have a service manual. I don't have a circuit either. Can someone point me in the right direction. BTW the battery on the cpu board what is it? is it the same as the 1650. One other thing on the brochure it mentioned a 1161 panoramic display, anyone seen one? I gather these are as rare as hens teeth.

73's Lee

--

Vy 73 de Jean-Claude, HB3YDH

#2996

From: "Gerry O'Hara" <gerryohara@...>
Date: Mon Jun 25, 2012 4:48 pm
Subject: RE: Newbie

g8guh

Lee,

I noted that the EUG website has ‘by request’ against the 1995 model (‘operator’s manual’) – may be worth emailing Chris Pettitt to see what he may have access to (g0eyo@...).

Gerry

From: eddystone_radio_users@... [mailto:eddystone_radio_users@...] On Behalf Of casy_ch@...
Sent: June-25-12 7:49 AM
To: eddystone_radio_users@...
Subject: Re: [eddystone_radio_users] Newbie

Am 25.06.2012 16:33, schrieb vk5abc:

Hello All
I have just joined and am seeking help, as I just just purchased a 1995/2 receiver. It has the failed bite test however I don't have a service manual. I don't have a circuit either. Can someone point me in the right direction. BTW the battery on the cpu board what is it? is it the same as the 1650. One other thing on the brochure it mentioned a 1161 panoramic display, anyone seen one? I gather these are as rare as hens teeth.

73's Lee

--

Vy 73 de Jean-Claude, HB3YDH

#2997

From: "L D Ritta" <vk5abc@...>
Date: Mon Jun 25, 2012 4:58 pm
Subject: RE: Newbie

vk5abc

Hello Gerry

I have already done that and he is on vacation but told me he does not have the service manual thanks.

73’s Lee.

From: eddystone_radio_users@... [mailto:eddystone_radio_users@...] On Behalf Of Gerry O'Hara
Sent: Tuesday, 26 June 2012 2:19 AM
To: eddystone_radio_users@...
Subject: RE: [eddystone_radio_users] Newbie

Lee,

I noted that the EUG website has ‘by request’ against the 1995 model (‘operator’s manual’) – may be worth emailing Chris Pettitt to see what he may have access to (g0eyo@...).

Gerry

Am 25.06.2012 16:33, schrieb vk5abc:

Hello All
I have just joined and am seeking help, as I just just purchased a 1995/2 receiver. It has the failed bite test however I don't have a service manual. I don't have a circuit either. Can someone point me in the right direction. BTW the battery on the cpu board what is it? is it the same as the 1650. One other thing on the brochure it mentioned a 1161 panoramic display, anyone seen one? I gather these are as rare as hens teeth.

73's Lee

--

Vy 73 de Jean-Claude, HB3YDH

#2998

From: g0eyo@...
Date: Fri Jun 29, 2012 2:59 pm
Subject: Looking for an EC10 Frequency Scale?

g0eyo