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Old 18th Aug 2014, 8:46 am   #21
Tazman1966
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Default Re: BRC 3k Thorn in my head.

Yes Dave and saves any stress on the EHT transformer if the tripler is faulty. Good luck!
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Old 18th Aug 2014, 4:44 pm   #22
gec2110
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Default Re: BRC 3k Thorn in my head.

A BU208 will not last long as a replacement for the R2010B, even the top of the range Toshiba variety of BU208A.

A BU326 will work.
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Old 18th Aug 2014, 6:09 pm   #23
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Default Re: BRC 3k Thorn in my head.

I found that the R2008 on the LTB was breaking down. Replacing this with a BU208 (Toshiba) and with the tripler removed I switched on and the set came to life with no fuse blowing. I connected the tripler and got a picture for around 10secs then a crack and the cut out operated. Resetting the trip and switching on I watched the tripler again after around 10 secs a flash and a crack from the tripler somewhere near the 24kV output to the tube so I guess the original fault was the tripler.
So I will have to go on a search for a replacement tripler.
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Old 21st Aug 2014, 10:31 am   #24
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Default Re: BRC 3k Thorn in my head.

Hi.

I purchased a number of triplers from EBay member ianyellowpinky1 a while back and I'm fairly sure he had a new 3000/3500 tripler available. It might be worth trying to contact him.

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Old 21st Aug 2014, 5:42 pm   #25
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Default Re: BRC 3K. Thorn in my head.

Thanks for that.
I have contacted him through e bay I will just wait to see if he replies.
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Old 21st Aug 2014, 7:28 pm   #26
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Default Re: BRC 3K. Thorn in my head.

Got a reply from Ian. Unfortunatly all have gone. Thanks anyway.
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Old 22nd Aug 2014, 8:31 am   #27
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Default Re: BRC 3K. Thorn in my head.

Have you replaced the line output tuning capacitor? It used to give a lot of trouble with early 3000's blowing up triplers and tubes. It may be intermittent. I have a quantity of the modified type somewhere in the capacitor stores. problem is they are now over 40 years old but have been stored in dry conditions. Just a thought, John.
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Old 22nd Aug 2014, 9:28 am   #28
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Default Re: BRC 3K. Thorn in my head.

This is I believe a NOS thorn 3000/3500 tripler if you can identify it as such I will send it to you FOC as I will never use it.
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Old 22nd Aug 2014, 1:17 pm   #29
Davewantsone
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Default Re: BRC 3K. Thorn in my head.

I can identify the securing lugs being in the right position, however the 3k tripler seems to have 5 connections not just 3 in your picture.
My tripler has the following outputs just listed not in any order.
1 8kv in
2 24KV out
3 focus
4 crt bias (-800V)
5 earth.
So if the tripler only has 3 connections unfortunatly it must not be a thorn 3k-3k5.
If anyone else can tell me different then of course I would take you up on your very generous offer.
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Old 22nd Aug 2014, 1:26 pm   #30
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Default Re: BRC 3K. Thorn in my head.

Looks like a Pye CT205 tripler.
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Old 22nd Aug 2014, 1:40 pm   #31
Davewantsone
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Default Re: BRC 3K. Thorn in my head.

Quote:
Originally Posted by Heatercathodeshort View Post
Have you replaced the line output tuning capacitor?
Thanks John.
Yes I have.
I did it two years ago when I got the set going and just recently. Its the insulation that is breaking down on the tripler. Its one of the old white type You can see the shape of the capacitors and the rectifier rods in the plastic all covered by a form of white sealant. It is probably well past its sell by date with the insulation breaking down!
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Old 22nd Aug 2014, 5:14 pm   #32
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Default Re: BRC 3K. Thorn in my head.

Try this one for looks (I am certain I have a new 3000 unit!) the sticker reads TS 25 11 TC V, again if it is right you are welcome to it.
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Old 22nd Aug 2014, 6:21 pm   #33
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Default Re: BRC 3K. Thorn in my head.

Thats the one
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Old 22nd Aug 2014, 9:22 pm   #34
Davewantsone
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Default Re: BRC 3K. Thorn in my head.

Sorry for my late reply but I have been out. Yes that is the correct one like Malc says. Its even got the correct focus-grid connector. I will of course pay for the postage and packing. I will send you a PM.
Thank you.

Last edited by Davewantsone; 22nd Aug 2014 at 9:29 pm.
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Old 22nd Aug 2014, 9:45 pm   #35
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Default Re: BRC 3K. Thorn in my head.

I have just noticed that the R2010B is listed by NR Bardwell of Sheffield, see here:

http://www.bardwells.co.uk/product/r2010b-transistor/

They also stock the R2008B. They're not exactly bargain of the year but appear to be genuine Texas Instruments devices so should be top grade parts.


Regards
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Old 22nd Aug 2014, 9:57 pm   #36
Davewantsone
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Default Re: BRC 3K. Thorn in my head.

Thanks Symon.
The R2010 fitted to my power board was OK it was the 140uF or 2u2F that was going S/c after a couple of seconds after switching on. The original fault is the tripler which was breaking down and causing the trip to operate and blowing the R2008 transistor on the LTB board. This developed into the above mentioned fault which was causing F603 to blow and the trip to operate.
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Old 23rd Aug 2014, 1:33 pm   #37
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Default Re: BRC 3K. Thorn in my head.

That's great news. Normally the first signs of trouble from that 140uf cap is a cogged verticals and an unpleasant whistling noise from the PSU.
I have never heard of a BU208A being used in these sets. I think it has a lot to do with the HT line to the line output stage only being 60v. BU208's were used widely in other all transistorised sets of the time, G8, RBM823 etc where the HT line was nearer the 200v mark.
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Old 23rd Aug 2014, 3:23 pm   #38
Davewantsone
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Default Re: BRC 3K. Thorn in my head.

I have not got round to trying them yet but I bought some BU536 to try in place of the R2010 or even the R2008. I wil get around to also trying a
BU208A in the LTB once I get the tripler. I have a spare LTB which does need the R2008 replacing. The collector current for a BU208A is sufficient and so is the wattage dissipation, the collector supply being only at 60V instead of 200V should not be a problem.
By the way I removed and replaced four components from the 60V circuit, to get it working. The mains rectifier and the capacitor across it plus the 2u2F and the 140uF. So it may not be the 140uF that was breaking down!
My logic with the tripler breaking down and drawing excess current, this caused a greater load which caused the rectifier diode to break down on load and go S/C. Which would blow the trip and the fuse. So I would suspect the mains rectifier diode.

Last edited by AC/HL; 23rd Aug 2014 at 7:06 pm. Reason: Pointless repetition of the previous post removed
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Old 26th Aug 2014, 3:29 pm   #39
Davewantsone
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Default Re: BRC 3K. Thorn in my head.

Tripler arrived today. (Thanks to generous gift from Hansomcommon.)
I have had the TV on for 3 hours without a crack or bang. So the replacement tripler has cured my fault. Watched "When the boat comes in" and a couple episodes of "On the buses"!
So the TV is back to working order. I still have the spare LTB and PSB to test but I will leave well alone.
Thanks to all who provide some help in getting this set going again. I will just have to remember not to leave it too long before switching it on. Two years was far too long.
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