Advice wanted on what TV to start on. - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Heatercathodeshort · 6th Jul 2017, 8:19 am

Agree Joe, great receivers but not so nice to work on with the twin chassis and the difficulty of working on them while the chassis is live. OK if you just want to blanket replace components but the problem with that is you don't learn anything.

The KB/ITT VC1-VC53 chassis are such good candidates that I forgot to mention them! The earlier 405 models from the OV30 onwards are also very easy to work on.

Just a general note. Avoid at all costs anything that has more than a hint of rust. This usually indicates that a considerable amount of damp has ingressed into the wound components particularly the LOPT. John

robin coleman · 6th Jul 2017, 7:32 pm

Thank you for your suggestions, I will have a look at what is available locally and may be I will find one. I will need to find some decent reading material. Looking on the you tube site I have seen people making the EHT safe. Is there a tool still available for this or an appropriate way of doing this? John I saw a lamp limiter you had on your bench on one of your write ups have you a diagram for how it is wired.

Regards, Robin.

Welsh Anorak · 7th Jul 2017, 2:38 pm

Hi
I assume you mean discharging the CRT? Early pre-war designs' EHT was NEVER safe - but I'm sure you wouldn't be lucky enough to get one of those.
I admit we used the 'crossed screwdrivers' technique for EHT discharge - great fun! However a slightly more advanced way was to use a flat well-insulated probe which you carefully introduced under the EHT cap having firstly connected a flying lead to the earthing strap (NOT the chassis). One TV used to supply these helpful gadgets though I can't remember which one. You could easily make your own, and perhaps incorporate a bleed resistor if you prefer.
Glyn

robin coleman · 7th Jul 2017, 7:57 pm

I will try to use the tool I think. I can remember our test engineer at Quad discharging electrolytics using a screwdriver to the chassis.

Regards, Robin.

robin coleman · 25th Jul 2017, 9:34 pm

I now have to build the lamp limiter. Thank you John. Now I need to find a suitable specimen locally and some suitable bed time reading.

Regards, Robin.

6th Jul 2017, 8:19 am	#21
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: Advice wanted on what TV to start on. Agree Joe, great receivers but not so nice to work on with the twin chassis and the difficulty of working on them while the chassis is live. OK if you just want to blanket replace components but the problem with that is you don't learn anything. The KB/ITT VC1-VC53 chassis are such good candidates that I forgot to mention them! The earlier 405 models from the OV30 onwards are also very easy to work on. Just a general note. Avoid at all costs anything that has more than a hint of rust. This usually indicates that a considerable amount of damp has ingressed into the wound components particularly the LOPT. John

6th Jul 2017, 7:32 pm	#22
robin coleman Hexode Join Date: Oct 2011 Location: Portsmouth, Hampshire, UK. Posts: 354	Re: Advice wanted on what TV to start on. Thank you for your suggestions, I will have a look at what is available locally and may be I will find one. I will need to find some decent reading material. Looking on the you tube site I have seen people making the EHT safe. Is there a tool still available for this or an appropriate way of doing this? John I saw a lamp limiter you had on your bench on one of your write ups have you a diagram for how it is wired. Regards, Robin.

7th Jul 2017, 2:38 pm	#23
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,927	Re: Advice wanted on what TV to start on. Hi I assume you mean discharging the CRT? Early pre-war designs' EHT was NEVER safe - but I'm sure you wouldn't be lucky enough to get one of those. I admit we used the 'crossed screwdrivers' technique for EHT discharge - great fun! However a slightly more advanced way was to use a flat well-insulated probe which you carefully introduced under the EHT cap having firstly connected a flying lead to the earthing strap (NOT the chassis). One TV used to supply these helpful gadgets though I can't remember which one. You could easily make your own, and perhaps incorporate a bleed resistor if you prefer. Glyn

7th Jul 2017, 7:57 pm	#24
robin coleman Hexode Join Date: Oct 2011 Location: Portsmouth, Hampshire, UK. Posts: 354	Re: Advice wanted on what TV to start on. I will try to use the tool I think. I can remember our test engineer at Quad discharging electrolytics using a screwdriver to the chassis. Regards, Robin.

25th Jul 2017, 9:34 pm	#25
robin coleman Hexode Join Date: Oct 2011 Location: Portsmouth, Hampshire, UK. Posts: 354	Re: Advice wanted on what TV to start on. I now have to build the lamp limiter. Thank you John. Now I need to find a suitable specimen locally and some suitable bed time reading. Regards, Robin.