Lockdown project - Sony TC-200 - Page 5 - UK Vintage Radio Repair and Restoration Discussion Forum

DMcMahon · 7th May 2020, 9:46 am

I got confused with the sequence of events because at Post 75 you got channel 2 working (by swapping over wiper connections) but then at Post 77 you said " keeping it playing while testing this has killed the Channel 1 pre amp".

So was killing channel 1 referring to what occurred before or post getting channel 2 working, also the final fix of the capacitor was on the output valve not the pre-amp ?

Just trying to understand it better. You must be very satisfied with fixing it.

Paulus.d · 8th May 2020, 2:04 pm

Yeah ... sorry , I was rushing trying to keep up with posts and other stuff so I got my wires crossed so to speak ....I didn't kill channel 1 , it took a long time to come back to playing after fading away while I had channel 2 playing ..
I did notice Chanel one being a little more noisy than 1, but I'll face that when the new transformer comes in ..A member on here is building me a new one .....

Yes I'm very pleased with it... the sound is a lttle toppy for my ears and the tone control don't do much but happy ....
Regards Paul

Paulus.d · 29th May 2020, 3:28 pm

Time for an update on my progress with this machine....
The output transformer came in from a very helpful member on here, Ed Dinning and after a minor hickup was working on both channels... so I was prepared to bung it back together when I noticed the output switch not working, again on channel 2. It did not respond to switch cleaner, in fact it made it worse, so I took the switch apart and cleaned it. Put back together, it played for 2 hours then channel 2 faded away like channel one did at the begining of this thread, so I changed the same cap on channel 2's transistor stage and fitted two AC 127's.

Its now working , it still has a strange issue, channel 1 is nice sounding, channel 2 is harsh, very top heavy, almost painful to my ears... I checked the frequency correction from the contacts to the PCB , there okay....
This part isn't logical to me as the speed switch s102 and s202 contacts seem to work in reverse to my understanding? the 470pf caps are switched out at 7 1/2 ips?
Regards Paul

ms660 · 29th May 2020, 5:02 pm

In the schematic the speed switch position looks to be correct, more -ve feedback on the high speed setting than on the low speed setting.

Lawrence.

Paulus.d · 29th May 2020, 5:12 pm

okay.... so I've got to figure out which channels at fault...either one is too high and stuck on or the other is low and won't kick in lol = paul

Paulus.d · 29th May 2020, 6:54 pm

Would this circuit be active during playback or record

?

ms660 · 29th May 2020, 7:03 pm

If you mean the EQ circuit then yes both on record (in effect high frequency Boost) and playback (in effect high frequency cut)

Lawrence.

Paulus.d · 29th May 2020, 8:01 pm

Right just played with it..... Channel onebehaves as it shoud ..there's a noticable change during record as the switch is made and broken. Channel 2 sounds hollow and empty on playback...it's switch makes no difference to the reording... the switch itself meters okay ..... i'll start with those pesky 470pf caps...
Paul

Paulus.d · 30th May 2020, 5:04 pm

Right ...I'm putting this one back away... another one to mark up as 'don't buy stuff from Ebay' Channel 1 now doesn't record but does playback..
I may come back to later ..but I'm wasting my and everyone else's time here

Regards Paul

7th May 2020, 9:46 am	#81
DMcMahon Dekatron Join Date: Apr 2019 Location: Worthing, West Sussex, UK. Posts: 6,600	Re: Lockdown project - Sony TC-200 I got confused with the sequence of events because at Post 75 you got channel 2 working (by swapping over wiper connections) but then at Post 77 you said " keeping it playing while testing this has killed the Channel 1 pre amp". So was killing channel 1 referring to what occurred before or post getting channel 2 working, also the final fix of the capacitor was on the output valve not the pre-amp ? Just trying to understand it better. You must be very satisfied with fixing it.

8th May 2020, 2:04 pm	#82
Paulus.d Hexode Join Date: Mar 2008 Location: Margate, Kent, UK. Posts: 355	Re: Lockdown project - Sony TC-200 Yeah ... sorry , I was rushing trying to keep up with posts and other stuff so I got my wires crossed so to speak ....I didn't kill channel 1 , it took a long time to come back to playing after fading away while I had channel 2 playing .. I did notice Chanel one being a little more noisy than 1, but I'll face that when the new transformer comes in ..A member on here is building me a new one ..... Yes I'm very pleased with it... the sound is a lttle toppy for my ears and the tone control don't do much but happy .... Regards Paul

29th May 2020, 3:28 pm	#83
Paulus.d Hexode Join Date: Mar 2008 Location: Margate, Kent, UK. Posts: 355	Re: Lockdown project - Sony TC-200 Time for an update on my progress with this machine.... The output transformer came in from a very helpful member on here, Ed Dinning and after a minor hickup was working on both channels... so I was prepared to bung it back together when I noticed the output switch not working, again on channel 2. It did not respond to switch cleaner, in fact it made it worse, so I took the switch apart and cleaned it. Put back together, it played for 2 hours then channel 2 faded away like channel one did at the begining of this thread, so I changed the same cap on channel 2's transistor stage and fitted two AC 127's. Its now working , it still has a strange issue, channel 1 is nice sounding, channel 2 is harsh, very top heavy, almost painful to my ears... I checked the frequency correction from the contacts to the PCB , there okay.... This part isn't logical to me as the speed switch s102 and s202 contacts seem to work in reverse to my understanding? the 470pf caps are switched out at 7 1/2 ips? Regards Paul

29th May 2020, 5:02 pm	#84
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Lockdown project - Sony TC-200 In the schematic the speed switch position looks to be correct, more -ve feedback on the high speed setting than on the low speed setting. Lawrence.

29th May 2020, 5:12 pm	#85
Paulus.d Hexode Join Date: Mar 2008 Location: Margate, Kent, UK. Posts: 355	Re: Lockdown project - Sony TC-200 okay.... so I've got to figure out which channels at fault...either one is too high and stuck on or the other is low and won't kick in lol = paul

29th May 2020, 6:54 pm	#86
Paulus.d Hexode Join Date: Mar 2008 Location: Margate, Kent, UK. Posts: 355	Re: Lockdown project - Sony TC-200 Would this circuit be active during playback or record?

29th May 2020, 7:03 pm	#87
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Lockdown project - Sony TC-200 If you mean the EQ circuit then yes both on record (in effect high frequency Boost) and playback (in effect high frequency cut) Lawrence.

29th May 2020, 8:01 pm	#88
Paulus.d Hexode Join Date: Mar 2008 Location: Margate, Kent, UK. Posts: 355	Re: Lockdown project - Sony TC-200 Right just played with it..... Channel onebehaves as it shoud ..there's a noticable change during record as the switch is made and broken. Channel 2 sounds hollow and empty on playback...it's switch makes no difference to the reording... the switch itself meters okay ..... i'll start with those pesky 470pf caps... Paul

30th May 2020, 5:04 pm	#89
Paulus.d Hexode Join Date: Mar 2008 Location: Margate, Kent, UK. Posts: 355	Re: Lockdown project - Sony TC-200 Right ...I'm putting this one back away... another one to mark up as 'don't buy stuff from Ebay' Channel 1 now doesn't record but does playback.. I may come back to later ..but I'm wasting my and everyone else's time here Regards Paul