BRC 2000 restoration. - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

gec2110 · 26th May 2011, 11:19 pm

Thanks Valveman49 for the 2000 info very good to read the articals in television were very good indeed

Electrical · 26th May 2011, 11:33 pm

Hello
The makers manual for the BRC 2000 Chassis is available in 14 parts in this post.
https://www.vintage-radio.net/forum/...ad.php?t=69056
Regards Stan.

Techman · 27th May 2011, 1:50 am

I had one of these BRC 2000s - along with several 3000s. I saved it for years along with dozens of other sets. It was a massive thing, but sadly when I moved house back in 1999, it, & nearly all of the other sets had to go to the tip.

I always intended to restore it, as even back in '99 it was quite an unusual survivor (& with it being the first solid state british colour set), but in the end it was just too large to bring to the new (smaller) house & had to go

brianc · 27th May 2011, 9:13 am

I must say that this thread almost makes me want to try my hand at a 2000 colour chassis. I built a set in the '70s using a Mullard decoder made by my own fair hand and CTV25 scan chassis (from Manor supplies). It worked for about 7 years and was passed on to a relative. Seeing the schematics for the 2000 reminded me of my rats nest. I did say "nearly" though, so probably won't go down that route but should I, then that's the set for me.

Welsh Anorak · 27th May 2011, 1:16 pm

Hi
Just a thought, but I'd be tempted to temporarily wire the system switch on the line TB into 625 and disable the solenoid for the moment as trouble here invariably destroys the output transistors. When it's all healthy again you can start trying the 405 section...
I used to find the top mounted regulator board got a bit warm and transistors used to go leaky - ISTR 2N3055s were a good replacement.
How's the convergence board? That did sometimes resemble toast!
Good luck - we'll be interested. I do have some very tired boards here if you're in need of a part.
Glyn

MALC SCOTT · 27th May 2011, 1:36 pm

Hi Glyn, the three fusible resistors on the psu are all sprung open. So no chance of the solenoids operating. I can see one previous repair on the convergence pcb. It looks in good nick. I have replaced all of the Callin electrolytics on the video pcb and done a blanket re-solder. The psu has been subject to the same treatment. The top regulator pcb has has a couple of duff caps changed and a good clean with foam cleanser, rinsed and dried out. I am now working on the line timebase pcb. There are quite a few of those black Callin caps need replacing as they are all leaking. The condition of the pcb,s is very good with very little signs of previous work. I am working my way through each pcb before i attempt to feed it mains. Keep your old boards handy, Cheers, Malc

oldticktock · 27th May 2011, 3:14 pm

Hi Malc,

I came across one of those black Callin electrolytics for the very first time last weekend on a BRC 1400 chassis. Immense stink and smoke, I put it on the Capacitance bridge and It's leakage was extreme, only holding 99.1V for a 350V cap. The picture shows the HUNTS Bridge with the NEON lit and the meter showing the level of leakage.

Like I say I'm used to suspecting Hunts and TCC but these Callins were new to me.

Chris

Steve_P · 27th May 2011, 5:23 pm

First thing to do is change all Callins caps on sight. In most cases, the nearest preferred value will do. Then bring it up over 24 hours, with the Power Supply only fitted. This is to bring up the caps.

Cheers,

Steve P.

Welsh Anorak · 30th May 2011, 1:20 pm

Hi
I think those caps were Irish, though I may be wrong - most Thorn sets of the period used them, though they used to last a bit better in their audio equipment. The main problem I found (besides unreliability) was the odd values they had and non-standard shapes.
I look forward to seeing the results, especially as you seem to have a good CRT.
Glyn

MALC SCOTT · 30th May 2011, 5:06 pm

Hi, here are some pics. The set took almost 20 mins to unwrap, it must have take Mikey 405 ages to parcel it up!

murphyv310 · 30th May 2011, 5:20 pm

Nice set Malc.
That would be ideal to construct a piggy back 405 line NTSC decoder for another conversion, surely someone has a 19 inch set I could get hold of!

MALC SCOTT · 30th May 2011, 5:20 pm

More pics of the inside and the regulator. Video, line timebase pcb,s after i had cleaned, re-caped and blanket solderd them.

Mikey405 · 30th May 2011, 6:26 pm

Quote:

Originally Posted by MALC SCOTT

Hi, here are some pics. The set took almost 20 mins to unwrap, it must have take Mikey 405 ages to parcel it up!

Oh it did Malc. I was going to send it to you but I couldn't get the first class stamp to stick to the parcel tape.

MALC SCOTT · 2nd Jun 2011, 9:55 am

Hi, i have replaced every Callin electrolytic ond numerous other brands. The smoothers all reformed. I have powerd up the set and the ht rails are all ok and the line/frame timebases are running. The problem now is no eht. The supply to VT7 eht generator transistor collector is missing. The system swich is clean.
I find it difficult to locate the source of this supply as the cct is not very clear.
Any ideas? Cheers, Malc.

ppppenguin · 2nd Jun 2011, 10:17 am

Power to the EHT unit is a bit contorted. The main unregulated supply comes from the PSU to the series pass transistor, VT6. Is this supply present? The output of the series pass goes via S1F which is on the linescan PCB. This could be bridged out in 625 for now. Could also be checked by cold tests. Finally regulated 66V is routed via the focus panel and SKT19 (pins 2/3) as a sort of interlock. The last bit of trickery is that the 0V rail on the EHT card is returned to main chassis via R3 (2R) on the PSU card.

Line drive comes from PLG11/2 to the base of the EHT output transistor VT7.

Nothing to stop you disconnecting the main power to the EHT card and using a variable DC supply to the top or tap of the EHT transformer. Just wind it up very gently until you get some EHT. Won't be stabilised but will tell you if the EHT generator is basically OK.

MALC SCOTT · 2nd Jun 2011, 11:18 am

Hi Jeffery, i have HT at the collector of VT6 but nothing at the emitter.

ppppenguin · 2nd Jun 2011, 11:51 am

VT6 could be duff or the control circuitry (all the rest of the stuff on the EHT card) could have a fault somewhere. Normal faultfinding with a meter needed. It's a fairly simple feedback stabilising system but because there's feedback any fault anywhere will upset virtually every voltage reading.

Many years ago when I last played with a 2000 (my first ever CTV, bought ex-rental) I think I used an external PSU to run up the EHT at first. Then nothing needs to work except VT7, transformer and tripler.

MALC SCOTT · 2nd Jun 2011, 12:05 pm

Whilst doing a few cold checks with the meter i noticed an unusual reading across the pre-set EHT pot. When i removed it, one of the legs to the track fell off. I am off to find a 22k pot to replace it with.

HamishBoxer · 2nd Jun 2011, 12:15 pm

Think it was VT7 on top regulator board that used to fail.

David

MALC SCOTT · 9th Jun 2011, 12:17 pm

Hi, after fitting a new pot and a couple of out of spec resistors on the eht generator board the voltages are about correct up to VT5. Ther are no emitter volts here. New transistor fitted and components around VT5 check ok. Could it be the current overload protection? Not sure how this operates (w2)

26th May 2011, 11:19 pm	#21
gec2110 Retired Dormant Member Join Date: Feb 2008 Location: Croydon, London, UK. Posts: 408	Re: BRC 2000 restoration. Thanks Valveman49 for the 2000 info very good to read the articals in television were very good indeed

26th May 2011, 11:33 pm	#22
Electrical Hexode Join Date: Jul 2008 Location: Gateshead, Tyne & Wear, UK. Posts: 337	Re: BRC 2000 restoration. Hello The makers manual for the BRC 2000 Chassis is available in 14 parts in this post. https://www.vintage-radio.net/forum/...ad.php?t=69056 Regards Stan. __________________ Junk accumulates to fill the space available.

27th May 2011, 1:50 am	#23
Techman Dekatron Join Date: Nov 2009 Location: Lincolnshire, UK. Posts: 5,000	Re: BRC 2000 restoration. I had one of these BRC 2000s - along with several 3000s. I saved it for years along with dozens of other sets. It was a massive thing, but sadly when I moved house back in 1999, it, & nearly all of the other sets had to go to the tip. I always intended to restore it, as even back in '99 it was quite an unusual survivor (& with it being the first solid state british colour set), but in the end it was just too large to bring to the new (smaller) house & had to go

27th May 2011, 9:13 am	#24
brianc Rest in Peace Join Date: Jun 2004 Location: Burghfield, Reading, Berkshire, UK, Posts: 1,055	Re: BRC 2000 restoration. I must say that this thread almost makes me want to try my hand at a 2000 colour chassis. I built a set in the '70s using a Mullard decoder made by my own fair hand and CTV25 scan chassis (from Manor supplies). It worked for about 7 years and was passed on to a relative. Seeing the schematics for the 2000 reminded me of my rats nest. I did say "nearly" though, so probably won't go down that route but should I, then that's the set for me.

27th May 2011, 1:16 pm	#25
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,927	Re: BRC 2000 restoration. Hi Just a thought, but I'd be tempted to temporarily wire the system switch on the line TB into 625 and disable the solenoid for the moment as trouble here invariably destroys the output transistors. When it's all healthy again you can start trying the 405 section... I used to find the top mounted regulator board got a bit warm and transistors used to go leaky - ISTR 2N3055s were a good replacement. How's the convergence board? That did sometimes resemble toast! Good luck - we'll be interested. I do have some very tired boards here if you're in need of a part. Glyn

27th May 2011, 1:36 pm	#26
MALC SCOTT Octode Join Date: Aug 2006 Location: Willington, County Durham, UK. Posts: 1,499	Re: BRC 2000 restoration. Hi Glyn, the three fusible resistors on the psu are all sprung open. So no chance of the solenoids operating. I can see one previous repair on the convergence pcb. It looks in good nick. I have replaced all of the Callin electrolytics on the video pcb and done a blanket re-solder. The psu has been subject to the same treatment. The top regulator pcb has has a couple of duff caps changed and a good clean with foam cleanser, rinsed and dried out. I am now working on the line timebase pcb. There are quite a few of those black Callin caps need replacing as they are all leaking. The condition of the pcb,s is very good with very little signs of previous work. I am working my way through each pcb before i attempt to feed it mains. Keep your old boards handy, Cheers, Malc __________________ Malc Scott

27th May 2011, 3:14 pm	#27
oldticktock Retired Dormant Member Join Date: Nov 2009 Location: Weardale, UK. Posts: 1,981	Re: BRC 2000 restoration. Hi Malc, I came across one of those black Callin electrolytics for the very first time last weekend on a BRC 1400 chassis. Immense stink and smoke, I put it on the Capacitance bridge and It's leakage was extreme, only holding 99.1V for a 350V cap. The picture shows the HUNTS Bridge with the NEON lit and the meter showing the level of leakage. Like I say I'm used to suspecting Hunts and TCC but these Callins were new to me. Chris Attached Thumbnails

27th May 2011, 5:23 pm	#28
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: BRC 2000 restoration. First thing to do is change all Callins caps on sight. In most cases, the nearest preferred value will do. Then bring it up over 24 hours, with the Power Supply only fitted. This is to bring up the caps. 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...?

30th May 2011, 1:20 pm	#29
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,927	Re: BRC 2000 restoration. Hi I think those caps were Irish, though I may be wrong - most Thorn sets of the period used them, though they used to last a bit better in their audio equipment. The main problem I found (besides unreliability) was the odd values they had and non-standard shapes. I look forward to seeing the results, especially as you seem to have a good CRT. Glyn

30th May 2011, 5:06 pm	#30
MALC SCOTT Octode Join Date: Aug 2006 Location: Willington, County Durham, UK. Posts: 1,499	Re: BRC 2000 restoration. Hi, here are some pics. The set took almost 20 mins to unwrap, it must have take Mikey 405 ages to parcel it up! Attached Thumbnails __________________ Malc Scott

30th May 2011, 5:20 pm	#31
murphyv310 Dekatron Join Date: Sep 2006 Location: Kilmarnock, Ayrshire, UK. Posts: 5,422	Re: BRC 2000 restoration. Nice set Malc. That would be ideal to construct a piggy back 405 line NTSC decoder for another conversion, surely someone has a 19 inch set I could get hold of! __________________ Cheers, Trevor. MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member

30th May 2011, 5:20 pm	#32
MALC SCOTT Octode Join Date: Aug 2006 Location: Willington, County Durham, UK. Posts: 1,499	Re: BRC 2000 restoration. More pics of the inside and the regulator. Video, line timebase pcb,s after i had cleaned, re-caped and blanket solderd them. Attached Thumbnails __________________ Malc Scott

2nd Jun 2011, 9:55 am	#34
MALC SCOTT Octode Join Date: Aug 2006 Location: Willington, County Durham, UK. Posts: 1,499	Re: BRC 2000 restoration. Hi, i have replaced every Callin electrolytic ond numerous other brands. The smoothers all reformed. I have powerd up the set and the ht rails are all ok and the line/frame timebases are running. The problem now is no eht. The supply to VT7 eht generator transistor collector is missing. The system swich is clean. I find it difficult to locate the source of this supply as the cct is not very clear. Any ideas? Cheers, Malc. __________________ Malc Scott

2nd Jun 2011, 10:17 am	#35
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: BRC 2000 restoration. Power to the EHT unit is a bit contorted. The main unregulated supply comes from the PSU to the series pass transistor, VT6. Is this supply present? The output of the series pass goes via S1F which is on the linescan PCB. This could be bridged out in 625 for now. Could also be checked by cold tests. Finally regulated 66V is routed via the focus panel and SKT19 (pins 2/3) as a sort of interlock. The last bit of trickery is that the 0V rail on the EHT card is returned to main chassis via R3 (2R) on the PSU card. Line drive comes from PLG11/2 to the base of the EHT output transistor VT7. Nothing to stop you disconnecting the main power to the EHT card and using a variable DC supply to the top or tap of the EHT transformer. Just wind it up very gently until you get some EHT. Won't be stabilised but will tell you if the EHT generator is basically OK.

2nd Jun 2011, 11:18 am	#36
MALC SCOTT Octode Join Date: Aug 2006 Location: Willington, County Durham, UK. Posts: 1,499	Re: BRC 2000 restoration. Hi Jeffery, i have HT at the collector of VT6 but nothing at the emitter. __________________ Malc Scott

2nd Jun 2011, 11:51 am	#37
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: BRC 2000 restoration. VT6 could be duff or the control circuitry (all the rest of the stuff on the EHT card) could have a fault somewhere. Normal faultfinding with a meter needed. It's a fairly simple feedback stabilising system but because there's feedback any fault anywhere will upset virtually every voltage reading. Many years ago when I last played with a 2000 (my first ever CTV, bought ex-rental) I think I used an external PSU to run up the EHT at first. Then nothing needs to work except VT7, transformer and tripler.

2nd Jun 2011, 12:05 pm	#38
MALC SCOTT Octode Join Date: Aug 2006 Location: Willington, County Durham, UK. Posts: 1,499	Re: BRC 2000 restoration. Whilst doing a few cold checks with the meter i noticed an unusual reading across the pre-set EHT pot. When i removed it, one of the legs to the track fell off. I am off to find a 22k pot to replace it with. __________________ Malc Scott

2nd Jun 2011, 12:15 pm	#39
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,935	Re: BRC 2000 restoration. Think it was VT7 on top regulator board that used to fail. David

9th Jun 2011, 12:17 pm	#40
MALC SCOTT Octode Join Date: Aug 2006 Location: Willington, County Durham, UK. Posts: 1,499	Re: BRC 2000 restoration. Hi, after fitting a new pot and a couple of out of spec resistors on the eht generator board the voltages are about correct up to VT5. Ther are no emitter volts here. New transistor fitted and components around VT5 check ok. Could it be the current overload protection? Not sure how this operates (w2) __________________ Malc Scott