Thanks Chris.
If V5A is not conducting, then its anode (pin9) will rise towards full B+ voltage.
So, as Chris says, concentrate on R39 and R40.
If V5A is not conducting, then its anode (pin9) will rise towards full B+ voltage.
So, as Chris says, concentrate on R39 and R40.
'If V5A is not conducting, then its anode (pin9) will rise towards full B+ voltage.'
Thanks Galu for that clarification - now it makes sense!
Here's a picture of the underside of V5 before I started work - I'm hopeful that I may have transposed a connection or two here:-
Thanks Galu for that clarification - now it makes sense!
Here's a picture of the underside of V5 before I started work - I'm hopeful that I may have transposed a connection or two here:-
Well, Donald, hopefully my interpretation of Chris' statement does make sense. My ploy is that if I talk enough rubbish an expert is sure to chime in! 😉
Looking at your photograph prompts me to ask the obvious question - did the amplifier work on both channels before you started renewing components?
Looking at your photograph prompts me to ask the obvious question - did the amplifier work on both channels before you started renewing components?
P.S. It's certainly busy around that valve base - good to have the working channel for comparison!
Thanks Galu - unfortunately the owner can't remember if both channels were working (!) and thought he was doing me a favour by removing the amplifier module from the case!
I won't be able to get access to the stereogram until Wednesday this week but meantime can I ask if V5A is not conducting would that cause the loss of the left-hand channel?
I won't be able to get access to the stereogram until Wednesday this week but meantime can I ask if V5A is not conducting would that cause the loss of the left-hand channel?
If that tube does not conduct, then the signal voltage will not be propagated in that channel.
It should be possible to get some useful data just by measuring the resistance to ground from each of the tube socket pins with the tubes out. A discrepancy there left and right points to a resistor with the wrong value or a capacitor that is leaking badly.
But then you have the tricky problem to decide how you fix it. Do you replace one dodgy shock absorber on a 50 year old car? (I am in this quandary myself with a current project).
It should be possible to get some useful data just by measuring the resistance to ground from each of the tube socket pins with the tubes out. A discrepancy there left and right points to a resistor with the wrong value or a capacitor that is leaking badly.
But then you have the tricky problem to decide how you fix it. Do you replace one dodgy shock absorber on a 50 year old car? (I am in this quandary myself with a current project).
I suspect you may have made a positional error when you earlier replaced some "dodgy" components.
You're in the fortunate position of having a working right channel, so do some resistance comparisons along the lines of OldHector's sage advice.
You're in the fortunate position of having a working right channel, so do some resistance comparisons along the lines of OldHector's sage advice.
'I suspect you may have made a positional error when you earlier replaced some "dodgy" components.'
As we suspected Galu I had indeed made a small positional error and transposed two components on the underside of V5A - not bad considering 99% of the other components were connected up correctly and I was doing it blind so to speak!
Good news is that I now have two working channels and the voltages on all four ECL82s are roughly matching! There is probably some more fine tuning I can do to match up both channels but for now I was happy to play 'Apache' by The Shadows which brightened up my day! What this does demonstrate, however, is the importance of taking detailed before and after pictures!
Now moving on to the Garrard 210 record deck as the auto-changer mechanism is very sticky and needs the usual degreasing and lubrication. Thanks to Vinyl Engine I have the Service Sheets for the Garrard 210.
As we suspected Galu I had indeed made a small positional error and transposed two components on the underside of V5A - not bad considering 99% of the other components were connected up correctly and I was doing it blind so to speak!
Good news is that I now have two working channels and the voltages on all four ECL82s are roughly matching! There is probably some more fine tuning I can do to match up both channels but for now I was happy to play 'Apache' by The Shadows which brightened up my day! What this does demonstrate, however, is the importance of taking detailed before and after pictures!
Now moving on to the Garrard 210 record deck as the auto-changer mechanism is very sticky and needs the usual degreasing and lubrication. Thanks to Vinyl Engine I have the Service Sheets for the Garrard 210.
Result! 
F.B.I. level success in fact!
The Garrard 210 is a classic autochanger, as seen in this stock image of another Pye G63.
I wonder what cartridge is currently fitted?
F.B.I. level success in fact!
The Garrard 210 is a classic autochanger, as seen in this stock image of another Pye G63.
I wonder what cartridge is currently fitted?
Of course good progress was only made thanks to the help of Forum members and I've learned all about these push-pull amps!
The original Garrard GCE12 cartridge has been replaced at some point with a BSR SX6M and it currently has what looks like a ST15 dual LP/LP stylus.
The amp module still has a bit of a hum which is not affected by the volume control? The large electrolytic smoothing and reservoir caps, the usual source of this type of hum, have been replaced so not sure what to try next?
The original Garrard GCE12 cartridge has been replaced at some point with a BSR SX6M and it currently has what looks like a ST15 dual LP/LP stylus.
The amp module still has a bit of a hum which is not affected by the volume control? The large electrolytic smoothing and reservoir caps, the usual source of this type of hum, have been replaced so not sure what to try next?
It may be normal and unavoidable for the circuit layout of this vintage amplifier to produce some background hum. Also, the speakers in this large stereogram will reproduce low frequencies more efficiently than the speaker in a small table radio.
If the hum is not audible beyond a distance of 1 metre from the speakers when no music is playing, and/or not noticeable at normal listening levels when music is playing, then I would leave well enough alone.
If the hum is not audible beyond a distance of 1 metre from the speakers when no music is playing, and/or not noticeable at normal listening levels when music is playing, then I would leave well enough alone.
'It may be normal and unavoidable for the circuit layout of this vintage amplifier to produce some background hum.'
I fully accept that statement and have extensive experience of this 'annoyance' in other vintage gear! I am, however, always interested in the source of any hum and what mitigating arrangements are in the circuit to reduce hum? Some minor mods are often available and I just wondered if anyone had any tips for this PYE G63? I note that V6 (EZ81) is a full wave rectifier so 100Hz should be easier to deal with than 50Hz.
Not wishing to stir up a hornet's nest can I ask if anyone has replaced the existing two core mains lead with a three core lead, connecting the earth wire to the chassis of both the PYE amp module and Garrard auto-changer?
'Is there a hum pot for the heaters? How are the heaters grounded?'
There is no evidence of a hum pot having been incorporated in the circuit? If we look at the circuit diagram in Post #7 above, is the role of the hum pot taken up by R23 and R24?
The heaters appear to share the same ground as the rest of the circuit - see diagrams in Posts #7 and #15 above?
I fully accept that statement and have extensive experience of this 'annoyance' in other vintage gear! I am, however, always interested in the source of any hum and what mitigating arrangements are in the circuit to reduce hum? Some minor mods are often available and I just wondered if anyone had any tips for this PYE G63? I note that V6 (EZ81) is a full wave rectifier so 100Hz should be easier to deal with than 50Hz.
Not wishing to stir up a hornet's nest can I ask if anyone has replaced the existing two core mains lead with a three core lead, connecting the earth wire to the chassis of both the PYE amp module and Garrard auto-changer?
'Is there a hum pot for the heaters? How are the heaters grounded?'
There is no evidence of a hum pot having been incorporated in the circuit? If we look at the circuit diagram in Post #7 above, is the role of the hum pot taken up by R23 and R24?
The heaters appear to share the same ground as the rest of the circuit - see diagrams in Posts #7 and #15 above?
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I must err on the side of caution, as I am no expert in vintage radio/record player renovation.
For safety reasons, I would stick to the original Pye configuration regarding the mains lead - particularly if this renovation was being done for someone else.
For safety reasons, I would stick to the original Pye configuration regarding the mains lead - particularly if this renovation was being done for someone else.
Those are the cathode bias resistors for the PP output stage: https://education.lenardaudio.com/en/14_valve_amps_4.html#:~:text=Cathode bias is mostly used in low cost,supply Voltage. 470R is selected for this explanation.
The Valve Wizard site gives information on reducing hum due to heater supplies: https://www.valvewizard.co.uk/heater.html
The above diagram is showing the new location for earthing the motor in order to make three core cable connection neater.
Is there currently continuity between your record deck chassis, motor and amplifier ground?
Is there currently continuity between your record deck chassis, motor and amplifier ground?
I always err on the side of caution and don't intend making any changes to the mains cable connections as I am aware of the liabilities that run with that risk!
Now that we have the amp module up and working to a satisfactory level it's now time to turn our attention to the Garrard Model 210 auto-changer.
All the moving parts on both sides of the Garrard were thoroughly degreased as there were known issues with the auto-changer mechanism failing to engage at start-up! Speed selector mechanism including the idler wheel, step lever and motor bearings were also treated and these know work ok.
The centre spindle was removed to enable access to the ball race to replace the missing ball bearing and the metal thrust washers, plastic washer and ball cage/bearings were lubricated with thin machine oil before reassembly as per the Service Sheet.
I do, however, still have the auto-changer start up problems even after re-lubricating all moving levers (grease) and bearings (oil)? The Garrard plays fine on manual but simply fails to engage on Auto? There is no sign of any remaining hardened grease so I'm a bit unsure as to where the problem lies?
Anyone done a Garrard Model 210 disassembly or have any experience of the problems I am describing?
Now that we have the amp module up and working to a satisfactory level it's now time to turn our attention to the Garrard Model 210 auto-changer.
All the moving parts on both sides of the Garrard were thoroughly degreased as there were known issues with the auto-changer mechanism failing to engage at start-up! Speed selector mechanism including the idler wheel, step lever and motor bearings were also treated and these know work ok.
The centre spindle was removed to enable access to the ball race to replace the missing ball bearing and the metal thrust washers, plastic washer and ball cage/bearings were lubricated with thin machine oil before reassembly as per the Service Sheet.
I do, however, still have the auto-changer start up problems even after re-lubricating all moving levers (grease) and bearings (oil)? The Garrard plays fine on manual but simply fails to engage on Auto? There is no sign of any remaining hardened grease so I'm a bit unsure as to where the problem lies?
Anyone done a Garrard Model 210 disassembly or have any experience of the problems I am describing?
Failure of an autochanger mechanism to engage is usually traceable to a siezed up cam gear.
The mechanism of the 210 is more complex than that of the later Garrard autochangers - if it were an AT60 I would know how to free the cam!
Freeing the cam gear may not be straightforward on this model.
What does the 210 service manual have to say about servicing the cam gear?
The mechanism of the 210 is more complex than that of the later Garrard autochangers - if it were an AT60 I would know how to free the cam!
Freeing the cam gear may not be straightforward on this model.
What does the 210 service manual have to say about servicing the cam gear?