Pye v4

[Lloyd 1985]

Hi, what you need to check is the current its drawing, if the bench psu has an ammeter on it just see what it reads, if not then put your meter set to read amps in series with the crt heater and see what it reads. it should be somewhere close to 0.3a. probably best to leave it connected up for a few minutes so it warms up and settles before taking a reading.

regards,
Lloyd

[oldticktock]

I tried the thermionic trick with the heaters powered by the Bench, tilted the set, gently tapped the neck with end of a rubberised screwdriver and I could set little particles drop off the health glow as now returned to the sort of normal glow one would expect from the CRT heater. I will give this a power again and see what happens.

Amps before were about 5 now its 3

[Lloyd 1985]

ooh, that sounds promissing!!

[oldticktock]

Never thought I would be so happy to see frame collapse, YES!

OTT back in business

[ppppenguin]

Originally Posted by oldticktock

Amps before were about 5 now its 3

Methinks you mean 0.5 and 0.3 amps. Well done for getting the tube back from the dead, let's hope it stays that way. You can put it back in the heater chain now.

[oldticktock]

Never took it out, just gave it the beans after confirming the heaters with bench supply and knocking the crud.

Yes .3 i dunno what it is with me and measurments lately, yesterday I had me drawing a 12cm EHT spark!!!!!! that explains the spikey hair

Now I've got to sort all the issues out, first of which is this buzzing which results in the line on screen pulsing with the buzzing

[Kevin19]

Yes well done!
I would try to sort this HT out re R131 then as think you have a probs there if you have not already done so! As you say in post this morning!
I see R131 is conected to C101 as you say! This cap C101 has not gone O/C has it? And hence why you resisitor lit up! As just having a quick look this is the HT feed line for Valves 1 to 5 maybe worth checking C101. And other caps resistors etc in this HT line

Kevin.

[Boom]

Chris what you need to do is measure the current with the heaters fed from your psu. If the heater is indeed shorting it will be up but bear in mind there is quite a lot of tolerance on heaters.

Dave

Ah I see that Jeffrey was typing at the same time.

[KeithsTV]

How much current is it taking? If it's more than 300mA that would indicate a partial short.

Keith

Ah I see others have suggested the same thing. Must remember to read all the posts before typing.

[Lloyd 1985]

well done getting the tube working! I've done some investigation into the smoking R131 problem, 2 caps to check which could cause this, C101 check it for a short, and also C18.

regards,
Lloyd.

[Station X]

Chris.

Try measuring the current taken by the heater. If the bench power supply doesn't have a meter to indicate current, connect a multimeter set to a suitable current range in series with the heater and PSU. The current should about 300mA or 0.3A. If it is then the tube heater is OK and the fault is elsewhere.

EDIT. I see I've duplicated several previous posts, which indicates that this is good advice.

[oldticktock]

Originally Posted by Lloyd 1985

investigation into the smoking R131 problem, 2 caps to check which could cause this, C101 check it for a short, and also C18

Hi Lloyd,

I was tracing the wiring lastnight from C101 to R131 and C102 and what was in that part of the circuit. It looks like C23 is the cap I mentioned in one of my earlier posts, the cap which looks like it was made by Slavador Dali, there's no way on earth that can be working and is between C101 + (12uf) and R131 + c102

I cannot for the life of me locate C18 it's not where it should be.

The 3rd tag along from the left looks like a long wire goes down to a valve pin, it does not, its just the photo angle, thats the wire that the bottom of the R131 resistor was connected to until I snipped it

[Station X]

C23 (Trader Sheet) could be the cause of the problem. Snip one end, replace R131 and see what happens. If C23 is the problem I wouldn't hold out too much hope of R22 and L9 having survived. In my opinion C14 or C18 are more likely candidates. If you lift one end of R17 this will split the RF HT supply in two and might help to localise the fault.

[oldticktock]

I refuse to have anymore bad luck, this PYE has had it's fair share now

[Station X]

Chris.

It was bad luck that the set got smashed in transit, but you've made an excellent job of fixing that.

Everything else is just down to faults which must be expected with a set of this age. If a waxie goes low it often takes a resistor with it. Nothing new there. It's not even certain yet that the tube heater has failed to a paritial short circuit. Low resistances are difficult to measure accurately. Try a current measurement as suggested. You may have a pleasant surprise.

It wouldn't be much fun if one could just buy a set, plug it in and find it worked, would it? Mere radios, not TVs, often take me months to repair. If I find a difficult problem I put the set to one side for a day or two and come back to it later. If necessary I seek advice on here. This set isn't a lost cause. True it seems to have more than a few faults, but these can be fixed.

[murphyv310]

Hi OTT
But that's what its all about! The V4 will of course have more problems to contend with than the simple sets from Bush, Regentone and the likes, you will see a much higher component count and for it's day a complex AGC circuit flywheel sync and proper black level circuits, one reason that the V4 is such a good performer and a set that drove many engineers round the bend in the 50's.
Now of course you are trying to fix a set that in all honesty (as did all the sets of the time) is 50 years past its sell by date, these sets were never intended to last as long as they have, it's a different ball game now replacing parts that probably never failed then.
You have done well to get as far as you have done and one thing to remember you are not a time served engineer with all the certificates so what you have done and learned is well Bl***y marvelous so give yourself a pat on the back and get on with the job in hand.
Good Luck

[Red to black]

Yes as Trevor says, Well Done so far!
I have been following your battles with interest, although not into valve stuff myself, I enjoy following the various members immense patience and dedication ressurecting 50+ year old sets.
I take my hat of to you good sirs, as I know how much time,effort,patience and sometimes expense you put in to do what you do.
I always follow these threads and the success stories and especially the before and after pics
Also the circuit diagrams to help follow the threads and the different theories, technical descriptions etc.
We all need help from time to time, and this is one of the reasons I joined this excellent forum, the levels of expertise and comradeship amongst the various members is a joy to behold!
Keep up the good work Lads!
Cheers,
Baz

[Lloyd 1985]

As everyone has said, your doing very well!! don't give up yet, I've had a couple of sets that have been right pigs to get working (style 70..) but I got there in the end! I still considder myself a learner at these things
I've had a good stare at your pictures, turned them upside down, then stared at the trader sheet, and I think that funny looking bit of melted goo is c18. C23 looks to be a bit closer to V4's base, and c18 is shown directly under L9 so I recon thats it. just snip one leg off for now. stick your meter on it on ohms range and see if it is shorted (by the looks of it it is!!)

regards,
Lloyd.

[Sideband]

Hi Chris. I'll also say well done! It can be very frustrating when you get problems like this. I was in the trade from 1970 up until 2008 and still had frustrating faults. I think you have done amazingly well since you have had no formal training.

I think I would now try and get the frame working and not worry about anything else just yet.


Keep it up! If you think it's getting too much, put it aside for a few days then go back to it. The number of times I've done this and gone straight to the fault after a break.....!

SB (Rich)

[oldticktock]

Hi before reading recent posts I changed the (Dali) cap, C14 which fell to pieces and C12 which also fell to pieces. This was done one at a time, each time R131 smokes away at which point I cut power.

Those hunts are totally wasted

See pics for current changes

Thank you all for your words of encouragement they mean a lot.

p.s.

0.003 is an odd value the only ones I had near this are the yellow WIMA's which are 0.0033, I know some will scream in horror at their use but it gets the job done.