Pye v4

[murphyv310]

1N4007's although a little slow will actually work on 405 although the lock wont be quite as good as 1N4148's, give them a try you've nothing to loose.

[oldticktock]

Ok I have ordered IN4148's and can put them in next week.

The IN4007's have a silver band on one end, the original M3's have a sealed metal end and what looks like a paxolin end. Which end of the IN4007 matches the M3 end

[murphyv310]

OK Easy way is to work it out from the circuit! The silver band (cathode) is the thick black solid end on the diode in the diagram not the triangular shaped part.

[oldticktock]

Scratch that I just found some IN4148 diodes Woo Hoo.

[oldticktock]

The In4148's have a black band at one end and the rest of the body is copper sort of colour, same principle I take it the band is the solid line

[murphyv310]

elementary stuff my dear Watson!

[oldticktock]

Ok I can't do this from the schematic. Each diode has a .001 cap and each diode has a 100K resistor. I need it simplified the pax end equates to, then I'm away.

I can wire the diodes together correctly but putting them in circuit is a 50 50 chance of round the wrong way

[oldticktock]

Is this it, I think it is, just need confirmation.

[murphyv310]

The anode of the original diode (M3) is connected to the metal part.
These diodes dont read on the diode test of a digital meter as they are high impedance.

[oldticktock]

Ok going to wire in I hope this cleans up the picture

[oldticktock]

Diodes in and its sort of better.


First pic is what happens if i use the large tuning wheel and go off test tone and get humm picture gets better.

Second picture is if I tune in test tone loud and clear, picture goes pants

[Sean Williams]

you arent far away now - looks like a lot of overloading now!

Excellent results, and I admire your tenacity!

Sean

[murphyv310]

You still have issues with the front end, wether its AGC, video or the IF strip I can't in all honesty say. The sync is also weak but that could be to do with the former. Without having the set on my bench and proper test equipment I feel I must now stop, at this point I cannot go any further. You could of course check your work for incorrect placement or values of components.
Why don't you take the set to an engineer that has a little spare time to give you some hands on experience?
My other problem is I have spent so much time here during my weeks holiday that I must spend some time with the missus before returning to work on Monday.
good luck


PS did you set up the line osc like I told you to do?

[oldticktock]

After what sean said, i put in a 12dB atten, helped quite a bit, still issues right side cut off, contrast either cuts picture out or seems to not do a lot. If you have the controls in other places contrast does a lot.

If I take the Atten out the picture goes overload again, so it needs the atten at present.

[oldticktock]

cannot remember what was the post #. I have the radio and TV service books and that has some info on the V4 setup.

Cheers Trevor appreciate all your advice

[Boom]

Still looks like cap' trouble to me

Dave

[oldticktock]

It looks like cogging on the left side but I have changed all caps except electrolytics and the flat round decoups.

MR2,MR4 & MR5 have been changed, but still there are MR1 ,3,6,7,8,9.

As PJL (Peter) said this bloomin set will end up having nearly everything changed before it gives up the fight.

Left hand side of the testcard is completely cut-off, not there at all

[oldticktock]

I've adjusted as best I can and this is what we get. left side is missing nothing brings helps.

[PJL]

You might as well change the diodes. They all look like signal diodes although only MR3 looks like it has much to do with the sync. Have you really done all the caps now?

[oldticktock]

All the waxies except one on the back which is on the fuses have been removed, still lots of low value pF's which are white and of course the flat rounds.

All elctrolytics are original