Goldring Lenco GL-75/Goodmans Module 80 Amp Issues - UK Vintage Radio Repair and Restoration Discussion Forum

Cameron · 5th Jun 2018, 10:32 am

I've got a Goldring Lenco GL-75 mounted in a plinth that also incorporates a Goodmans Module 80 amplifier. It dates from 1971-1974. I've had it since I was a teenager, I've always looked after it and it's given me years and years of faultless service.

A few days ago, we had a power cut. When it came back on, the volume of the Goodmans Amp had dropped slightly and last night, the right channel went silent.

I've tried all the sources (phono/auxiliary/FM) and it's still dead in the right channel. I've swapped the speaker cables over, and it's still got nothing in the right channel. I've had the front off it and cleaned the switch contacts (which have given me trouble in the past) and still no joy. Even through the headphone socket, there's no channel on the right.

What do you think has happened to it?

Thanks in advance, Cameron.

Edward Huggins · 5th Jun 2018, 2:42 pm

Given the age of this, it has served you very well up to now. Without the amp in front of me, it sounds like either a power rail supply issue to that channel or a circuit/transistor failure in that channel, esp. if it has had a voltage surge. You have conducted all the basic checks well. Do you have any experience of fault finding/voltage measuring?

Ted Kendall · 5th Jun 2018, 6:34 pm

First port of call is the output stage fuses, I'd say.

RojDW48 · 5th Jun 2018, 8:37 pm

Do the headphones run off the pre-amp stage in this model? Might indicate a fault there.

Cameron · 5th Jun 2018, 9:27 pm

Sadly my knowledge of electronics ends at the basic tests I've done! This record player means a lot to me and it's always been maintained and looked after regardless of cost during my ownership. But nothing this bad has happened yet. It's been in my family since it was new, but it wasn't used until I got hold of it about 15 years ago.

Ted points out to check the output fuses - I didn't realise that there would be such things! Where are they located, do you know? I can check those. I've had the whole thing apart a few times for cleaning etc...

I've approached a Hi-Fi repair specialist in Nottingham who said it is too old for him to repair, and recommended a general electronics repair shop. My instinct tells me to hold out and find someone who actually knows this TT/Amp rather than entrust it to a shop that mostly repairs TVs. I've posted a help wanted ad here, but so far had no replies.

michamoo · 5th Jun 2018, 10:42 pm

This old post may help?

https://www.vintage-radio.net/forum/...ad.php?t=76070

Edward Huggins · 6th Jun 2018, 9:18 am

I have great sympathy for the OP. Most of today's Hi Fi repairers would consider this as being now "beyond economic repair" whilst Flat Screen TV Engineers would probably take just one look and go cross-eyed. These early transistor receivers do need a bit of effort and searching for parts, but I'm sure if the OP persists with a call for help on here, he may find all the help he needs. Or search online wider afield, but maybe expect to pay £100 plus.

Cameron · 6th Jun 2018, 4:49 pm

I don’t care how much it costs to fix it, I just need to find someone who will! I’ve had an offer of help from the Welsh Borders but ideally I’d like to be able to take it to someone because I don’t trust anyone to courier it. Whenever we’ve moved house it’s always gone with me in the car rather than be left at the hands of the removal people! I don’t mind travelling within a 60 mile radius or so, and being right in the centre of the country, I’d have thought there would be someone who could fix it within a reasonable distance.

qualityten · 6th Jun 2018, 8:39 pm

There is a Goodmans module 90 amplifier for sale in EBay at present. I believe this is the same amp as is in the 80. This gives you the option running the amp and turntable separately. Just a thought. You will know that the GL75 responds well to being put in a solid plinth. See LencoHeaven for lots of info.

Michael Maurice · 6th Jun 2018, 9:47 pm

I may be able to help you, I'll send you a PM

ben · 6th Jun 2018, 10:21 pm

Quote:

Originally Posted by Cameron

Even through the headphone socket, there's no channel on the right.

Surely there's a clue that the output transistors are probably okay. This suggests that the preamp or even headshell contacts (to the OP: try removing and cleaning them) are at fault.

michamoo · 6th Jun 2018, 11:44 pm

Sometimes the Headphones are also driven from the output stages via resistors though Ben. He did say there was no audio from the radio either on that channel.

crackle · 7th Jun 2018, 3:58 pm

If your Module 80 has the same amp circuits as the my forty forty then I have an amp going spare, see. https://www.radiomuseum.org/r/goodma..._module80.html
Try and determine if you have outputs on both channels at the tape out sockets.
Lets see some photos of the insides and in particular the power amp boards, if the tape outputs are both working, then swapping the power amp circuits with my ones should fix it.
Mike

JohnBHanson · 10th Jun 2018, 6:42 pm

Looking at the service sheet and photo of the amp board. Your initial check should be fuse FS4. This is on the power supply to the right hand channel power amp.

Also just so everyone knows, the headphone output is via resistors from the speaker output - so the fact that the right hand channel is dead on headphones does not indicate anything.

See attachments for service sheet and photo of fuse to check.

Ted Kendall · 10th Jun 2018, 10:20 pm

As I said in post 3...

Cameron · 11th Jun 2018, 6:48 pm

Thanks for all your replies.

I've now opened it up and checked the FS4 fuse, and it's fine.

I've double checked the wires on the cartridge, but they're fine. The right channel output is affected across all the sources, so I think it's amplifier based rather than the pre-amp.

Attached are some photos of the power amp boards and general bits inside.

Interestingly, I've just tried the tape out into my Hi-Fi and it's completely dead. No output on either channel on both the Phono and FM source. I've tried it with both the 'tape' button depressed (which is how I think it operates) and without. Perhaps this helps to narrow down the fault?

PS. I forgot to add, in the days leading up to the failure, the output volume was dropping and the bass knob was becoming less effective. I've never needed to turn the volume control more than half-way on this amp, but the morning that the right channel failed, it was up around the 2/3rds mark, which I've never had before.

buggies · 11th Jun 2018, 7:51 pm

I know zilch about the amplifier but the first picture looks to me like a badly repaired diode bridge with one missing?

crackle · 11th Jun 2018, 7:55 pm

Quote:

Originally Posted by Cameron

I've now opened it up and checked the FS4 fuse, and it's fine.

Interestingly, I've just tried the tape out into my Hi-Fi and it's completely dead. No output on either channel on both the Phono and FM source. I've tried it with both the 'tape' button depressed (which is how I think it operates) and without. Perhaps this helps to narrow down the fault?

Hi
Yes I agree about the bridge diodes. Is there one on the other side of the board.

Just to double check, you did check the fuse actually on the power amp printed circuit board.

Also sorry to go over things but did you connect to the tape socket using the correct 5 pin din plug with pins 3 & 5 connected (I think that's correct for tape out on an amp. someone please correct me.)

Mike

Cameron · 11th Jun 2018, 10:17 pm

There's not one on the other side of the board, no. It's not been repaired during my ownership (around 10-15 years) and it was last used in the 1970s before that. To my knowledge, it wasn't used at all by the first owner (a close family friend) who actually got it on an insurance swindle(!) as she taught dancing at a local hall and her Dansette was stolen. She claimed for this Goodmans/Lenco because she could slow down the records to teach the dances. She got her karma though, as the unit was far too heavy to carry into the hall each week! So it was relegated to the top of her wardrobe until she gave it to me when clearing out, 30 years later. So who knows if it actually possibly left the factory like this?

I checked the fuse in the white holder on the circuit board, and then the other two just for good measure!

I've got the correct 5-pin DIN socket as I run a 3.5mm jack into the auxiliary usually, so I just swapped it over to the tape input and changed the end of the RCA line to connect it to my other amplifier's spare input to check it. Absolutely no sound whatsoever came though, but touching the RCAs together produced a 'buzz', so I know that my modern amp wasn't at fault.

Ted Kendall · 11th Jun 2018, 11:44 pm

No, the tape output appears on pins 1 and 4 of the DIN. If you seek the tape output with a lead going to pins 3 and 5, at best you may get a very thin and quiet signal, caused by capacitive coupling across the socket.

5th Jun 2018, 10:32 am	#1
Cameron Retired Dormant Member Join Date: Oct 2010 Location: Nottingham, Nottinghamshire, UK. Posts: 56	Goldring Lenco GL-75/Goodmans Module 80 Amp Issues I've got a Goldring Lenco GL-75 mounted in a plinth that also incorporates a Goodmans Module 80 amplifier. It dates from 1971-1974. I've had it since I was a teenager, I've always looked after it and it's given me years and years of faultless service. A few days ago, we had a power cut. When it came back on, the volume of the Goodmans Amp had dropped slightly and last night, the right channel went silent. I've tried all the sources (phono/auxiliary/FM) and it's still dead in the right channel. I've swapped the speaker cables over, and it's still got nothing in the right channel. I've had the front off it and cleaned the switch contacts (which have given me trouble in the past) and still no joy. Even through the headphone socket, there's no channel on the right. What do you think has happened to it? Thanks in advance, Cameron.

5th Jun 2018, 2:42 pm	#2
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,328	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues Given the age of this, it has served you very well up to now. Without the amp in front of me, it sounds like either a power rail supply issue to that channel or a circuit/transistor failure in that channel, esp. if it has had a voltage surge. You have conducted all the basic checks well. Do you have any experience of fault finding/voltage measuring? __________________ Edward.

5th Jun 2018, 6:34 pm	#3
Ted Kendall Dekatron Join Date: Jul 2008 Location: Kington, Herefordshire, UK. Posts: 3,670	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues First port of call is the output stage fuses, I'd say.

5th Jun 2018, 8:37 pm	#4
RojDW48 Nonode Join Date: Jun 2014 Location: Bristol, UK. Posts: 2,074	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues Do the headphones run off the pre-amp stage in this model? Might indicate a fault there. __________________ '....don't go mistaking Paradise for that home across the road!' (Bob Dylan)

5th Jun 2018, 9:27 pm	#5
Cameron Retired Dormant Member Join Date: Oct 2010 Location: Nottingham, Nottinghamshire, UK. Posts: 56	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues Sadly my knowledge of electronics ends at the basic tests I've done! This record player means a lot to me and it's always been maintained and looked after regardless of cost during my ownership. But nothing this bad has happened yet. It's been in my family since it was new, but it wasn't used until I got hold of it about 15 years ago. Ted points out to check the output fuses - I didn't realise that there would be such things! Where are they located, do you know? I can check those. I've had the whole thing apart a few times for cleaning etc... I've approached a Hi-Fi repair specialist in Nottingham who said it is too old for him to repair, and recommended a general electronics repair shop. My instinct tells me to hold out and find someone who actually knows this TT/Amp rather than entrust it to a shop that mostly repairs TVs. I've posted a help wanted ad here, but so far had no replies.

5th Jun 2018, 10:42 pm	#6
michamoo Hexode Join Date: May 2006 Location: Cambridge, Cambs. UK. Posts: 469	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues This old post may help? https://www.vintage-radio.net/forum/...ad.php?t=76070 __________________ If smoking is so bad for you, how come it cures kippers?

6th Jun 2018, 9:18 am	#7
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,328	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues I have great sympathy for the OP. Most of today's Hi Fi repairers would consider this as being now "beyond economic repair" whilst Flat Screen TV Engineers would probably take just one look and go cross-eyed. These early transistor receivers do need a bit of effort and searching for parts, but I'm sure if the OP persists with a call for help on here, he may find all the help he needs. Or search online wider afield, but maybe expect to pay £100 plus. __________________ Edward.

6th Jun 2018, 4:49 pm	#8
Cameron Retired Dormant Member Join Date: Oct 2010 Location: Nottingham, Nottinghamshire, UK. Posts: 56	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues I don’t care how much it costs to fix it, I just need to find someone who will! I’ve had an offer of help from the Welsh Borders but ideally I’d like to be able to take it to someone because I don’t trust anyone to courier it. Whenever we’ve moved house it’s always gone with me in the car rather than be left at the hands of the removal people! I don’t mind travelling within a 60 mile radius or so, and being right in the centre of the country, I’d have thought there would be someone who could fix it within a reasonable distance.

6th Jun 2018, 8:39 pm	#9
qualityten Octode Join Date: Feb 2009 Location: Wallasey, UK. Posts: 1,312	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues There is a Goodmans module 90 amplifier for sale in EBay at present. I believe this is the same amp as is in the 80. This gives you the option running the amp and turntable separately. Just a thought. You will know that the GL75 responds well to being put in a solid plinth. See LencoHeaven for lots of info.

6th Jun 2018, 9:47 pm	#10
Michael Maurice Moderator Join Date: Feb 2006 Location: Wembley, Middlesex Posts: 7,224	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues I may be able to help you, I'll send you a PM __________________ Forum Moderator http://www.michaelmauricerepairs.co.uk/

6th Jun 2018, 11:44 pm	#12
michamoo Hexode Join Date: May 2006 Location: Cambridge, Cambs. UK. Posts: 469	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues Sometimes the Headphones are also driven from the output stages via resistors though Ben. He did say there was no audio from the radio either on that channel. __________________ If smoking is so bad for you, how come it cures kippers?

7th Jun 2018, 3:58 pm	#13
crackle Rest in Peace Join Date: Mar 2011 Location: Basildon, Essex, UK. Posts: 4,100	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues If your Module 80 has the same amp circuits as the my forty forty then I have an amp going spare, see. https://www.radiomuseum.org/r/goodma..._module80.html Try and determine if you have outputs on both channels at the tape out sockets. Lets see some photos of the insides and in particular the power amp boards, if the tape outputs are both working, then swapping the power amp circuits with my ones should fix it. Mike

10th Jun 2018, 10:20 pm	#15
Ted Kendall Dekatron Join Date: Jul 2008 Location: Kington, Herefordshire, UK. Posts: 3,670	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues As I said in post 3...

11th Jun 2018, 6:48 pm	#16
Cameron Retired Dormant Member Join Date: Oct 2010 Location: Nottingham, Nottinghamshire, UK. Posts: 56	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues Thanks for all your replies. I've now opened it up and checked the FS4 fuse, and it's fine. I've double checked the wires on the cartridge, but they're fine. The right channel output is affected across all the sources, so I think it's amplifier based rather than the pre-amp. Attached are some photos of the power amp boards and general bits inside. Interestingly, I've just tried the tape out into my Hi-Fi and it's completely dead. No output on either channel on both the Phono and FM source. I've tried it with both the 'tape' button depressed (which is how I think it operates) and without. Perhaps this helps to narrow down the fault? PS. I forgot to add, in the days leading up to the failure, the output volume was dropping and the bass knob was becoming less effective. I've never needed to turn the volume control more than half-way on this amp, but the morning that the right channel failed, it was up around the 2/3rds mark, which I've never had before. Attached Thumbnails

11th Jun 2018, 7:51 pm	#17
buggies Heptode Join Date: Jan 2009 Location: West Lothian, UK. Posts: 761	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues I know zilch about the amplifier but the first picture looks to me like a badly repaired diode bridge with one missing? __________________ George

11th Jun 2018, 10:17 pm	#19
Cameron Retired Dormant Member Join Date: Oct 2010 Location: Nottingham, Nottinghamshire, UK. Posts: 56	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues There's not one on the other side of the board, no. It's not been repaired during my ownership (around 10-15 years) and it was last used in the 1970s before that. To my knowledge, it wasn't used at all by the first owner (a close family friend) who actually got it on an insurance swindle(!) as she taught dancing at a local hall and her Dansette was stolen. She claimed for this Goodmans/Lenco because she could slow down the records to teach the dances. She got her karma though, as the unit was far too heavy to carry into the hall each week! So it was relegated to the top of her wardrobe until she gave it to me when clearing out, 30 years later. So who knows if it actually possibly left the factory like this? I checked the fuse in the white holder on the circuit board, and then the other two just for good measure! I've got the correct 5-pin DIN socket as I run a 3.5mm jack into the auxiliary usually, so I just swapped it over to the tape input and changed the end of the RCA line to connect it to my other amplifier's spare input to check it. Absolutely no sound whatsoever came though, but touching the RCAs together produced a 'buzz', so I know that my modern amp wasn't at fault.

11th Jun 2018, 11:44 pm	#20
Ted Kendall Dekatron Join Date: Jul 2008 Location: Kington, Herefordshire, UK. Posts: 3,670	Re: Goldring Lenco GL-75/Goodmans Module 80 Amp Issues No, the tape output appears on pins 1 and 4 of the DIN. If you seek the tape output with a lead going to pins 3 and 5, at best you may get a very thin and quiet signal, caused by capacitive coupling across the socket.