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Trying to repair an EB-35mk1

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  • Martin
    Hi, new to the group, ive been lurking for a while! A work colleague gave me an Eddystone EB-35 mk1 as a restoration project. MW seems to work, but most of the
    Message 1 of 5 , Aug 1, 2008
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      Hi,

      new to the group, ive been lurking for a while!

      A work colleague gave me an Eddystone EB-35 mk1 as a restoration
      project. MW seems to work, but most of the other ranges are poor, FM
      is totally dead. There are no obvious faults for these ranges other
      than for LW. Coil L6 has been smashed at some point and is missing
      apart from the remains of its base.

      I havent done too much work on this as yet, my OU course is more
      pressing, but wish to get it working for my son to use. Hes only 4
      1/2 but already quite well versed in radio (cant avoid it having a
      radio tech/ham for a dad!) so i have two questions for the group -

      1. i'd like some general advice on restoring this model please.
      Should i do a blanket replacement of the electrolytics etc? Im not
      overly concerned with authenticity, although i do draw the line at
      swapping out the trannies for silicon types.

      2. Can anyone help me source a replacement for L6? I would like to
      get LW working again. I cut my teeth as it were on LW and MW, late
      nights listening to these bands while watching the rain from my
      bedroom window. And the odd noises i could hear soon took me to HF
      listening and on to amateur radio. Even now my greatest listening
      pleasure comes from weather stations on RTTY, Fax etc, and the sound
      of 'sailing by' still haunts my listening. In fact ive just listened
      to the R4 shipping forcast for the first time in years, via sky
      satellite, but somehow the magic is lost that way.


      regards

      Martin G7MRV
    • Gerry O'Hara
      Hello Martin and welcome to the Forum! I would start by contacting Ian Nutt to see if he has a replacement L6 in stock (also, he has just posted some lists of
      Message 2 of 5 , Aug 2, 2008
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        Hello Martin and welcome to the Forum!

         

        I would start by contacting Ian Nutt to see if he has a replacement L6 in stock (also, he has just posted some lists of parts on the EUG website, so perhaps check there first).  As for FM being dead, I would suspect TR12 and/or TR13.  However, if you have a signal genny, I would start by making sure the IF strip is working ok/aligned on both 465kHz and 10.7MHz (see manual for details).  Once this if confirmed ok, I would align the AM front-end per the manual and then start troubleshooting the circuitry around TR12/13.  The bandswitch may also be the culpit – try some switch cleaner and work the switch some.

         

        You may want to check out the ‘Early Semiconductor Lore’ and ‘Radio Receiver Fault Finding’ Technical Shorts on the EUG website for some more tips and maybe someone with ‘first-hand’ specific EB35 knowledge can help more? (unfortunately I do not possess one).

         

        FYI, I have just finished restoring my EC10 and have started ‘Part 2’ of the write-up – I have been busy this evening troubleshooting the audio stages which I found to be noisy after a month or so of not using the set – all bias resistors in the first AF stage were contributing to it (particularly a 15Kohm one) – sounded like frying eggs – much better now, only a slight hiss with the AF gain turned down (typical for an OC71).

         

        Keep us posted on progress!

         

        Good luck & 73

         

        Gerry, VE7GUH

         


        From: eddystone_radio_users@... [mailto:eddystone_radio_users@...] On Behalf Of Martin
        Sent: August-01-08 5:10 PM
        To: eddystone_radio_users@...
        Subject: [eddystone_radio_users] Trying to repair an EB-35mk1

         

        Hi,

        new to the group, ive been lurking for a while!

        A work colleague gave me an Eddystone EB-35 mk1 as a restoration
        project. MW seems to work, but most of the other ranges are poor, FM
        is totally dead. There are no obvious faults for these ranges other
        than for LW. Coil L6 has been smashed at some point and is missing
        apart from the remains of its base.

        I havent done too much work on this as yet, my OU course is more
        pressing, but wish to get it working for my son to use. Hes only 4
        1/2 but already quite well versed in radio (cant avoid it having a
        radio tech/ham for a dad!) so i have two questions for the group -

        1. i'd like some general advice on restoring this model please.
        Should i do a blanket replacement of the electrolytics etc? Im not
        overly concerned with authenticity, although i do draw the line at
        swapping out the trannies for silicon types.

        2. Can anyone help me source a replacement for L6? I would like to
        get LW working again. I cut my teeth as it were on LW and MW, late
        nights listening to these bands while watching the rain from my
        bedroom window. And the odd noises i could hear soon took me to HF
        listening and on to amateur radio. Even now my greatest listening
        pleasure comes from weather stations on RTTY, Fax etc, and the sound
        of 'sailing by' still haunts my listening. In fact ive just listened
        to the R4 shipping forcast for the first time in years, via sky
        satellite, but somehow the magic is lost that way.

        regards

        Martin G7MRV

      • ian nutt
        Martin, The coil you need is I believe part number D3518. I have these available in stock if you would like to email me directly. 73 s, Ian M0ECQ To:
        Message 3 of 5 , Aug 2, 2008
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          Martin,
           
          The coil you need is I believe part number D3518.
           
          I have these available in stock if you would like to email me directly.
           
          73's,
           
          Ian M0ECQ






          To: eddystone_radio_users@...
          From: barfield673@...
          Date: Sat, 2 Aug 2008 00:10:13 +0000
          Subject: [eddystone_radio_users] Trying to repair an EB-35mk1


          Hi,

          new to the group, ive been lurking for a while!

          A work colleague gave me an Eddystone EB-35 mk1 as a restoration
          project. MW seems to work, but most of the other ranges are poor, FM
          is totally dead. There are no obvious faults for these ranges other
          than for LW. Coil L6 has been smashed at some point and is missing
          apart from the remains of its base.

          I havent done too much work on this as yet, my OU course is more
          pressing, but wish to get it working for my son to use. Hes only 4
          1/2 but already quite well versed in radio (cant avoid it having a
          radio tech/ham for a dad!) so i have two questions for the group -

          1. i'd like some general advice on restoring this model please.
          Should i do a blanket replacement of the electrolytics etc? Im not
          overly concerned with authenticity, although i do draw the line at
          swapping out the trannies for silicon types.

          2. Can anyone help me source a replacement for L6? I would like to
          get LW working again. I cut my teeth as it were on LW and MW, late
          nights listening to these bands while watching the rain from my
          bedroom window. And the odd noises i could hear soon took me to HF
          listening and on to amateur radio. Even now my greatest listening
          pleasure comes from weather stations on RTTY, Fax etc, and the sound
          of 'sailing by' still haunts my listening. In fact ive just listened
          to the R4 shipping forcast for the first time in years, via sky
          satellite, but somehow the magic is lost that way.

          regards

          Martin G7MRV


        • Martin
          Hi Gerry, thanks for your reply, I have made a start, firstly giving the potentiometers and the switches a good soaking with servisol, then taking voltage
          Message 4 of 5 , Aug 2, 2008
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            Hi Gerry, thanks for your reply,

            I have made a start, firstly giving the potentiometers and the
            switches a good soaking with servisol, then taking voltage
            measurements of the transistors and comparing them with the
            published values. Most fall reasonably close. The exception was TR4,
            where all were very low. I gave it a good crack with the screwdriver
            and they all came up, and now i can hear FM stations!

            The first thing to work on though i think is the AF stages. Of the
            few MW and FM stations i can receive, the distortion is terrible. I
            suspect the electrolytics. Once i have that dealt with i shall work
            forward to the IF.

            I havent as yet had the signal generator on it. My equipment is a
            Marconi 2955 communications test set, but im not sure it goes down
            as far as 465kHz

            Its a start, at least! Ive linked out the AF input connection (no
            use to me, and just another part to cause problems), and reused the
            Tape connection as a DC input so i can run from the bench PSU. I
            need to find a suitable plug for the antenna sockets.

            One query - in the manual it says about adjusting for the 'outer'
            peak, and about secondary cores? now, ive never had to tackle double
            tuned coils before, so any advice on handling these beasties would
            be very welcome!

            Ian, i shall email you shortly concerning L6, cheers,

            Regards

            Martin

            --- In eddystone_radio_users@..., "Gerry O'Hara"
            <gerryohara@...> wrote:
            >
            > Hello Martin and welcome to the Forum!
            >
            >
            >
            > I would start by contacting Ian Nutt to see if he has a
            replacement L6 in
            > stock (also, he has just posted some lists of parts on the EUG
            website, so
            > perhaps check there first). As for FM being dead, I would suspect
            TR12
            > and/or TR13. However, if you have a signal genny, I would start
            by making
            > sure the IF strip is working ok/aligned on both 465kHz and 10.7MHz
            (see
            > manual for details). Once this if confirmed ok, I would align the
            AM
            > front-end per the manual and then start troubleshooting the
            circuitry around
            > TR12/13. The bandswitch may also be the culpit - try some switch
            cleaner
            > and work the switch some.
            >
            >
            >
            > You may want to check out the 'Early Semiconductor Lore'
            and 'Radio Receiver
            > Fault Finding' Technical Shorts on the EUG website for some more
            tips and
            > maybe someone with 'first-hand' specific EB35 knowledge can help
            more?
            > (unfortunately I do not possess one).
            >
            >
            >
            > FYI, I have just finished restoring my EC10 and have started 'Part
            2' of the
            > write-up - I have been busy this evening troubleshooting the audio
            stages
            > which I found to be noisy after a month or so of not using the
            set - all
            > bias resistors in the first AF stage were contributing to it
            (particularly a
            > 15Kohm one) - sounded like frying eggs - much better now, only a
            slight hiss
            > with the AF gain turned down (typical for an OC71).
            >
            >
            >
            > Keep us posted on progress!
            >
            >
            >
            > Good luck & 73
            >
            >
            >
            > Gerry, VE7GUH
            >
            >
            >
            > _____
            >
            > From: eddystone_radio_users@...
            > [mailto:eddystone_radio_users@...] On Behalf Of
            Martin
            > Sent: August-01-08 5:10 PM
            > To: eddystone_radio_users@...
            > Subject: [eddystone_radio_users] Trying to repair an EB-35mk1
            >
            >
            >
            > Hi,
            >
            > new to the group, ive been lurking for a while!
            >
            > A work colleague gave me an Eddystone EB-35 mk1 as a restoration
            > project. MW seems to work, but most of the other ranges are poor,
            FM
            > is totally dead. There are no obvious faults for these ranges
            other
            > than for LW. Coil L6 has been smashed at some point and is missing
            > apart from the remains of its base.
            >
            > I havent done too much work on this as yet, my OU course is more
            > pressing, but wish to get it working for my son to use. Hes only 4
            > 1/2 but already quite well versed in radio (cant avoid it having a
            > radio tech/ham for a dad!) so i have two questions for the group -
            >
            > 1. i'd like some general advice on restoring this model please.
            > Should i do a blanket replacement of the electrolytics etc? Im not
            > overly concerned with authenticity, although i do draw the line at
            > swapping out the trannies for silicon types.
            >
            > 2. Can anyone help me source a replacement for L6? I would like to
            > get LW working again. I cut my teeth as it were on LW and MW, late
            > nights listening to these bands while watching the rain from my
            > bedroom window. And the odd noises i could hear soon took me to HF
            > listening and on to amateur radio. Even now my greatest listening
            > pleasure comes from weather stations on RTTY, Fax etc, and the
            sound
            > of 'sailing by' still haunts my listening. In fact ive just
            listened
            > to the R4 shipping forcast for the first time in years, via sky
            > satellite, but somehow the magic is lost that way.
            >
            > regards
            >
            > Martin G7MRV
            >
          • Gerry O'Hara
            Sounds good Martin - I forgot to mention the sharp crack on the head with the butt of a screwdriver trick! - I tried that on the OC171 s in my EC10 but it
            Message 5 of 5 , Aug 2, 2008
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              Sounds good Martin – I forgot to mention the ‘sharp crack on the head with the butt of a screwdriver’ trick! – I tried that on the OC171’s in my EC10 but it didn’t work.

               

              As for the double-tuned transformer cores, these are usually adjusted using a hexagonal plastic trim tool with an extended narrow shaft section between the hex head and the normal diameter shaft: you poke the tool through the top core, wind the lower core clockwise (out) and back in to the first peak to adjust.  When done, pull the tool back into the upper core and adjust the upper core anticlockwise (out) and back in again to the first peak to adjust.  Repeat as necessary.

               

              73

               

              Gerry

               


              From: eddystone_radio_users@... [mailto:eddystone_radio_users@...] On Behalf Of Martin
              Sent: August-02-08 1:27 PM
              To: eddystone_radio_users@...
              Subject: [eddystone_radio_users] Re: Trying to repair an EB-35mk1

               

              Hi Gerry, thanks for your reply,

              I have made a start, firstly giving the potentiometers and the
              switches a good soaking with servisol, then taking voltage
              measurements of the transistors and comparing them with the
              published values. Most fall reasonably close. The exception was TR4,
              where all were very low. I gave it a good crack with the screwdriver
              and they all came up, and now i can hear FM stations!

              The first thing to work on though i think is the AF stages. Of the
              few MW and FM stations i can receive, the distortion is terrible. I
              suspect the electrolytics. Once i have that dealt with i shall work
              forward to the IF.

              I havent as yet had the signal generator on it. My equipment is a
              Marconi 2955 communications test set, but im not sure it goes down
              as far as 465kHz

              Its a start, at least! Ive linked out the AF input connection (no
              use to me, and just another part to cause problems), and reused the
              Tape connection as a DC input so i can run from the bench PSU. I
              need to find a suitable plug for the antenna sockets.

              One query - in the manual it says about adjusting for the 'outer'
              peak, and about secondary cores? now, ive never had to tackle double
              tuned coils before, so any advice on handling these beasties would
              be very welcome!

              Ian, i shall email you shortly concerning L6, cheers,

              Regards

              Martin

              --- In eddystone_radio_ users@yahoogroup s.co.uk, "Gerry O'Hara"
              <gerryohara@ ...> wrote:

              >
              > Hello Martin and welcome to the Forum!
              >
              >
              >
              > I would start by contacting Ian Nutt to see if he has a
              replacement L6 in
              > stock (also, he has just posted some lists of parts on the EUG
              website, so
              > perhaps check there first). As for FM being dead, I would suspect
              TR12
              > and/or TR13. However, if you have a signal genny, I would start
              by making
              > sure the IF strip is working ok/aligned on both 465kHz and 10.7MHz
              (see
              > manual for details). Once this if confirmed ok, I would align the
              AM
              > front-end per the manual and then start troubleshooting the
              circuitry around
              > TR12/13. The bandswitch may also be the culpit - try some switch
              cleaner
              > and work the switch some.
              >
              >
              >
              > You may want to check out the 'Early Semiconductor Lore'
              and 'Radio Receiver
              > Fault Finding' Technical Shorts on the EUG website for some more
              tips and
              > maybe someone with 'first-hand' specific EB35 knowledge can help
              more?
              > (unfortunately I do not possess one).
              >
              >
              >
              > FYI, I have just finished restoring my EC10 and have started 'Part
              2' of the
              > write-up - I have been busy this evening troubleshooting the audio
              stages
              > which I found to be noisy after a month or so of not using the
              set - all
              > bias resistors in the first AF stage were contributing to it
              (particularly a
              > 15Kohm one) - sounded like frying eggs - much better now, only a
              slight hiss
              > with the AF gain turned down (typical for an OC71).
              >
              >
              >
              > Keep us posted on progress!
              >
              >
              >
              > Good luck & 73
              >
              >
              >
              > Gerry, VE7GUH
              >
              >
              >
              > _____
              >
              > From: eddystone_radio_ users@yahoogroup s.co.uk
              > [mailto:eddystone_radio_ users@yahoogroup s.co.uk]
              On Behalf Of
              Martin
              > Sent: August-01-08 5:10 PM
              > To: eddystone_radio_ users@yahoogroup s.co.uk
              > Subject: [eddystone_radio_ users] Trying to repair an EB-35mk1
              >
              >
              >
              > Hi,
              >
              > new to the group, ive been lurking for a while!
              >
              > A work colleague gave me an Eddystone EB-35 mk1 as a restoration
              > project. MW seems to work, but most of the other ranges are poor,
              FM
              > is totally dead. There are no obvious faults for these ranges
              other
              > than for LW. Coil L6 has been smashed at some point and is missing
              > apart from the remains of its base.
              >
              > I havent done too much work on this as yet, my OU course is more
              > pressing, but wish to get it working for my son to use. Hes only 4
              > 1/2 but already quite well versed in radio (cant avoid it having a
              > radio tech/ham for a dad!) so i have two questions for the group -
              >
              > 1. i'd like some general advice on restoring this model please.
              > Should i do a blanket replacement of the electrolytics etc? Im not
              > overly concerned with authenticity, although i do draw the line at
              > swapping out the trannies for silicon types.
              >
              > 2. Can anyone help me source a replacement for L6? I would like to
              > get LW working again. I cut my teeth as it were on LW and MW, late
              > nights listening to these bands while watching the rain from my
              > bedroom window. And the odd noises i could hear soon took me to HF
              > listening and on to amateur radio. Even now my greatest listening
              > pleasure comes from weather stations on RTTY, Fax etc, and the
              sound
              > of 'sailing by' still haunts my listening. In fact ive just
              listened
              > to the R4 shipping forcast for the first time in years, via sky
              > satellite, but somehow the magic is lost that way.
              >
              > regards
              >
              > Martin G7MRV
              >

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