New Telly Arrival month: Fergy 3710, Fergy 3712, Bush CTV 1120 & Beovision 3200-SJ

Unfortunately it's possible that the LOPT has caused it's demise but if the drive is intermittent then this could also be responsible.

Only one way to find out I suppose and that's put in another VT401 and see. The original was a rather rusty cased affair.

Indeed VT401 is toast, I don't have any BU105/02 but do have BDX32 and R2781

BDX32 or R2781 will be fine but you will need to add the following mod.

I'm lazy so have just found a BU206  ? 

Back in business with a BU206.

I have to say the line hold (L405) is very knife edge, even carefully removing the twiddle stick can upset it, as does tapping the can. I removed the core to check and its OK. Will check for dry joints tomorrow, that's me done for today.

I could have NOS  BU105. I will check tomorrow, Malc.

Concentrate on this area, as I said earlier look at the drive when the low EHT occurs. It sounds like the line is going way off frequency, the transistor will not like it and probably get rather hot.

LOPT failure is pretty rare, usually an obvious burnup to the core, intermittent ones are extremely rare.

I think I may have mislead, its not going wildly off frequency, just enough that the picture floats left or right sometimes a little quicker than others. When I get it locked, the test card occasionally judders and wants to pull left or right then you have this balancing act to do on L405, Its certainly not going way off frequency.

Traced the jittery line hold to a cracked trace between R401 & R402. Line now stable.

I've done my best with the convergence, its Ok-ish, but many of the pots are iffy or need cleaning. Every now and then its gets upset and a tap to the panel or pot 5 corrects red misalignment. I'm going to remove the board, clean and or replace pots that need it, hopefully will get some stability.

Line hold is rock solid.

The blue tilt pot always burnt out on these sets. I have loads of NOS Rediffusion Mk1  convergence pots if you can use them, Malc.

Posted by: Jayceebee

Beovision 3000 excellent, so you won't need central heating anymore or was it an exaggeration? 12HG7 luminance output was difficult or impossible to obtain but I don't think that's the case anymore.

I was just reading up on the 3000/3200 circuit and turned an even whiter shade than my current pale complexion......... The EHT generator in the early beo I picked up provides near instantaneous 7mA at 25kV   ? ? ?  

I know nothing about what mains derived pre-war sets produce but I think we're in the same lethal ball park but  at 7kV?

I might just hide from this set for some considerable time.

175W that is quite a bite!!!! ouch ? 

That's the peak current it can deliver - I suspect the sustained current will be less but nonetheless it is worth erring on the side of caution: the Barco CTVM3 monitors (which had fully regulated EHT) could pack a punch too. As long as you carry out safe working practices (which we know you do) you will not come to any harm. However, be prepared to see how mediocre other TV sets are after you've seen this B&O in operation!

With mains EHT the voltage was low but so was the source impedance... I believe there's an Americanism that goes along the lines of "it's the volts that jolts but the mills that kills"  

I noticed Neil29 on the ukvr site is giving away what looks like a Korting hybrid ctv, Malc.

Yes.... I spotted that too, just two month's since Mikey405 offered it up on UKVRRR, I wouldn't think Mike would be too impressed if it does end up being dumped! Hopefully someone will save it from that fate, too nice to be scrapped.

Interesting factoid: I used a Korting Vienna rear cover to complete my Baird 8724 rebuild

Yes, a very nice set by the look of it. I'm sure it will not be dumped, someone will have it. I would, if closer to Neil.

@crustytv

ohh those beovision 3000 series from late 60ies /first 70ies is huges as an automobile and heavy like a moutain, and was NOT for beginners, 360 watt in use here in Denmark 🙁 you dont need to turn on extra heat 😛 , the two line transformer system was really insane, but it works when it work