Tv62 - Page 11 - UK Vintage Radio Repair and Restoration Discussion Forum

oldticktock · 10th Apr 2010, 2:53 pm

pin1 4.3
pin2 2.6
pin3 2.5
pin4 4.3
pin5 4.4
pin6 167.4
pin7 12.7
pin8 172.7
pin9 108

Steve_P · 10th Apr 2010, 2:56 pm

Shouldn't Pin 1 be rather higher?

http://www.r-type.org/exhib/aam0081.htm

Cheers,

Steve P.

Station X · 10th Apr 2010, 3:00 pm

I'm no expert, but I suggest rechecking R19 and disconnecting C14.

Boom · 10th Apr 2010, 3:06 pm

Quote:

Originally Posted by Station X

I'm no expert, but I suggest rechecking R19 and disconnecting C14.

Good idea. What voltage do you have across C14 itself Chris? I think you said the tubes A1 is low. The frame osc' and the A1 are both fed from the same point (R37).

Dave

oldticktock · 10th Apr 2010, 3:13 pm

One end of c14 read 0.1v the other end that meets R19 is 4.7v

Boom · 10th Apr 2010, 3:15 pm

Chris fly to R37 (100k)! It's either that or C14 itself.

Station X · 10th Apr 2010, 3:16 pm

Disconnect one end of C14 and measure the voltage on pin 1 again. If Ok replace C14. If not check the voltage on both ends of R19.

oldticktock · 10th Apr 2010, 3:28 pm

R37 measures 105k, i've just clipped one end of C14 out that junctions with R19&R37 readings coming

pin 1 voltage 14.6

PJL · 10th Apr 2010, 3:44 pm

We have been round this loop before, last time you measured (post 177) it was 400V on the hot end of R19!

Try swapping the PCL83 with the other one.

oldticktock · 10th Apr 2010, 3:51 pm

PCL was brand new fitted yesterday.

With C14 clipped out R19 measure 4.6v one end and 14.0 the other

Station X · 10th Apr 2010, 3:54 pm

Either the HT for the PCL83 has disappeared or it's being pulled down by something. As the PCL83 was changed yesterday it's a likely candidate despite being brand new. Try changing it.

oldticktock · 10th Apr 2010, 3:55 pm

Do I leave C14 clipped out?

Boom · 10th Apr 2010, 3:57 pm

How can you have 400V at R19 in post 177 and 4.7V now? I can't see that a faulty PCL83 would drag the line down that much anyway.

Dave

Station X · 10th Apr 2010, 3:58 pm

Quote:

Do I leave C14 clipped out?

Leave it out for the moment to eliminate it from enquiries.

PJL · 10th Apr 2010, 4:01 pm

Is the meter on AC or DC volts? All measurements need to be DC.

oldticktock · 10th Apr 2010, 4:12 pm

This is where i start to despair

On my digital bench meter set to read DC i get 325v on one end and 7.6v the other end of R19.

With my AVO model 7, which I hate! I get 215v and 4.5v

Oh and new pcl83 in in place now

I take it that C14 is a standard cap not Electrolytic, if that is being the case and its duff then I do not have a 2uf replacement.

Boom · 10th Apr 2010, 4:21 pm

C14 is marked on the circuit as an electrolytic. If the voltage readings are indeed correct then it isn't likely to be C14 but do you have one to make sure? Those measurements are probably correct. The Avo will drag the line down. It sounds like the oscillator has stalled.

Why are you getting all these different readings though Chris? Do you have dodgy meter leads maybe?

Dave

oldticktock · 10th Apr 2010, 4:44 pm

Yep checked the schematic and its electrolytic. I think trouble i've been at this, allowing for lastnight sleep 16hours and i'm not thinking straight.

Just had a sanity break and a cuppa, I have 2uf electrolytics so I will clip one in.

Lleads are from an avo multiminor plugged into a digi bench meter, been reading fine until today. The AVO7 has the original heavy duty leads. I won't blame my tools guess it's just me being a plank somewhere along the line.

Chris

Station X · 10th Apr 2010, 4:51 pm

If C14 is very leaky then reconnecting it will bring the voltage down again. If it isn't the voltage will stay high.

If it's leaky and the earthed end is lifted, conecting a voltmeter between the lifted lead and earth will give a high voltage reading. If the reading is zero then the cap isn't leaking.

oldticktock · 10th Apr 2010, 4:57 pm

I have clipped in a new 2uf and have the meter clipped on the + end watching it rise over the last 5 mins started at 199v now its at 275v and climbing

At 293V now and still climbing

Think it may have topped out at 296V

0v on neg end of C14
296v on + end of C14
296v one side of R19
6.9v on other side of R19
6.9v on pin1 of PCL83

296v on R37/R19 junction
343v on R37 other end

10th Apr 2010, 2:53 pm	#201
oldticktock Retired Dormant Member Join Date: Nov 2009 Location: Weardale, UK. Posts: 1,981	Re: Tv62 pin1 4.3 pin2 2.6 pin3 2.5 pin4 4.3 pin5 4.4 pin6 167.4 pin7 12.7 pin8 172.7 pin9 108

10th Apr 2010, 2:56 pm	#202
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Tv62 Shouldn't Pin 1 be rather higher? http://www.r-type.org/exhib/aam0081.htm Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

10th Apr 2010, 3:00 pm	#203
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Tv62 I'm no expert, but I suggest rechecking R19 and disconnecting C14. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

10th Apr 2010, 3:13 pm	#205
oldticktock Retired Dormant Member Join Date: Nov 2009 Location: Weardale, UK. Posts: 1,981	Re: Tv62 One end of c14 read 0.1v the other end that meets R19 is 4.7v

10th Apr 2010, 3:15 pm	#206
Boom Retired Dormant Member Join Date: Jan 2007 Location: Westbury, Wiltshire, UK. Posts: 2,451	Re: Tv62 Chris fly to R37 (100k)! It's either that or C14 itself.

10th Apr 2010, 3:16 pm	#207
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Tv62 Disconnect one end of C14 and measure the voltage on pin 1 again. If Ok replace C14. If not check the voltage on both ends of R19. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

10th Apr 2010, 3:28 pm	#208
oldticktock Retired Dormant Member Join Date: Nov 2009 Location: Weardale, UK. Posts: 1,981	Re: Tv62 R37 measures 105k, i've just clipped one end of C14 out that junctions with R19&R37 readings coming pin 1 voltage 14.6

10th Apr 2010, 3:44 pm	#209
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: Tv62 We have been round this loop before, last time you measured (post 177) it was 400V on the hot end of R19! Try swapping the PCL83 with the other one.

10th Apr 2010, 3:51 pm	#210
oldticktock Retired Dormant Member Join Date: Nov 2009 Location: Weardale, UK. Posts: 1,981	Re: Tv62 PCL was brand new fitted yesterday. With C14 clipped out R19 measure 4.6v one end and 14.0 the other

10th Apr 2010, 3:54 pm	#211
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Tv62 Either the HT for the PCL83 has disappeared or it's being pulled down by something. As the PCL83 was changed yesterday it's a likely candidate despite being brand new. Try changing it. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

10th Apr 2010, 3:55 pm	#212
oldticktock Retired Dormant Member Join Date: Nov 2009 Location: Weardale, UK. Posts: 1,981	Re: Tv62 Do I leave C14 clipped out?

10th Apr 2010, 3:57 pm	#213
Boom Retired Dormant Member Join Date: Jan 2007 Location: Westbury, Wiltshire, UK. Posts: 2,451	Re: Tv62 How can you have 400V at R19 in post 177 and 4.7V now? I can't see that a faulty PCL83 would drag the line down that much anyway. Dave

10th Apr 2010, 4:01 pm	#215
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: Tv62 Is the meter on AC or DC volts? All measurements need to be DC.

10th Apr 2010, 4:12 pm	#216
oldticktock Retired Dormant Member Join Date: Nov 2009 Location: Weardale, UK. Posts: 1,981	Re: Tv62 This is where i start to despair On my digital bench meter set to read DC i get 325v on one end and 7.6v the other end of R19. With my AVO model 7, which I hate! I get 215v and 4.5v Oh and new pcl83 in in place now I take it that C14 is a standard cap not Electrolytic, if that is being the case and its duff then I do not have a 2uf replacement. Last edited by oldticktock; 10th Apr 2010 at 4:19 pm.

10th Apr 2010, 4:21 pm	#217
Boom Retired Dormant Member Join Date: Jan 2007 Location: Westbury, Wiltshire, UK. Posts: 2,451	Re: Tv62 C14 is marked on the circuit as an electrolytic. If the voltage readings are indeed correct then it isn't likely to be C14 but do you have one to make sure? Those measurements are probably correct. The Avo will drag the line down. It sounds like the oscillator has stalled. Why are you getting all these different readings though Chris? Do you have dodgy meter leads maybe? Dave

10th Apr 2010, 4:44 pm	#218
oldticktock Retired Dormant Member Join Date: Nov 2009 Location: Weardale, UK. Posts: 1,981	Re: Tv62 Yep checked the schematic and its electrolytic. I think trouble i've been at this, allowing for lastnight sleep 16hours and i'm not thinking straight. Just had a sanity break and a cuppa, I have 2uf electrolytics so I will clip one in. Lleads are from an avo multiminor plugged into a digi bench meter, been reading fine until today. The AVO7 has the original heavy duty leads. I won't blame my tools guess it's just me being a plank somewhere along the line. Chris

10th Apr 2010, 4:51 pm	#219
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Tv62 If C14 is very leaky then reconnecting it will bring the voltage down again. If it isn't the voltage will stay high. If it's leaky and the earthed end is lifted, conecting a voltmeter between the lifted lead and earth will give a high voltage reading. If the reading is zero then the cap isn't leaking. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

10th Apr 2010, 4:57 pm	#220
oldticktock Retired Dormant Member Join Date: Nov 2009 Location: Weardale, UK. Posts: 1,981	Re: Tv62 I have clipped in a new 2uf and have the meter clipped on the + end watching it rise over the last 5 mins started at 199v now its at 275v and climbing At 293V now and still climbing Think it may have topped out at 296V 0v on neg end of C14 296v on + end of C14 296v one side of R19 6.9v on other side of R19 6.9v on pin1 of PCL83 296v on R37/R19 junction 343v on R37 other end Last edited by oldticktock; 10th Apr 2010 at 5:13 pm.