Newbee PYE LV30

[beltinge bore]

Hello all.

This is my first post and cry for help. Just as a bit of background info. Up to now in my limited telly experience I have managed to revive a Bush TV24, Bush T57, PYE LV30C and a lovely old TC335 EKCO. My only tools are an ancient AVO 8 and a couple of digital multimeter/cap testers.

The LV30 I am working on at present has a rusty chassis and the dirtiest green valve pins I have ever seen. I have done the usual checks and applied juice via a variac (after snipping mains filter cap) No valve heaters so suspected mainsdropper which turned out to be O/C on all windings. Replacing same gave me valve heaters and speaker hum no sound with Aurora connected.

No sign of life from the screen. After changing the PZ30 I now have faint sound, good strong line whistle, normal HT and all valves glow except the EY51 EHT rectifier. I have a good 3/8” (1cm) spark from the EY51 anode and a small spark from the PL38 cap. I have changed the EY51 for a NOS item this has made no difference.

My question is do I go on a capacitor changing fest or can someone kindly point in the right direction to achieve a bit of life on the screen please.

Many thanks for reading this your advice would be appreciated.

Regards Steve

[Heatercathodeshort]

Just a very quick reply. I suspect the EHT heater winding on the LOPT is O/C. Disconnect the EY51 and measure the resistance of the heater winding. It should be very low. Check your new EY51 is not O/C! You can connect a 6.3v pilot lamp across the EHT heater terminals and this should light if the transformer is good. You appear to have enough AC on the anode end to prove the stage is operating reasonably. It might be 'green spot' on the windings or lead out wires. John.

[Peter.N.]

Hi Steve

I don't think a 3/8" spark is long enough, I would suspect the LOPT has got damp over the years, leave it running for a while and see if it gets warm, if it does suspect internal leakage through damp

It had probably taken a very long time for the moisture to penetrate and will take a long time to dry out, removing the transformer and leaving it in an airing cupboard for some weeks will often dry it out.

If its not getting warm the fault could be elsewhere, check the line boost capacitor, if this is o/c it will cause a reduction in EHT. Check for anything that is getting hot, that may lead you to the fault.

Peter

[Peter.N.]

Gazumped again.

[beltinge bore]

Many thanks for speedy reply.

Tested old EY51 heater when removed which tested OK (17 ohms I think) NOS EY51 tested the same. One lead on the old EY51 broke, this raised my hopes that I might get lucky with a new one.

Tested LOPT heater winding's as John suggested they appear to be O/C. In the words of my wife's favourite crooner Where Do I Go From Here?

Just a quick thank you to young John it was only his Crib notes on the Forum that enabled me to get my Ekco 300 series working.

Regards and many thanks Steve.

[Heatercathodeshort]

It is not the end of all hope. You can fit a stick solid state rectifier in place of the EY51. It may also be possible to hand wind the few turns yourself if the winding is on the outside of the bobbin which it usually is.
Peter has mentioned capacitors that must be replaced if the line output stage is to operate to full efficency. Excellent advice. John.

[beltinge bore]

Thanks John I know this must be very boring as a thread but I am a relative novice at this. Could you recommend a rectifier to replace the EY51?

Now confession time. I had a another LV30 in the garage loft this looked far worse than the 1st one (very corroded chassis no speaker tatty cabinet no back etc). After removing a panel pin that was soldered across FS2 (I kid you not) I decided to show it some mains. O/C dropper Jury rigged I got fizzy sound line whistle & EY51 glowing. Now decision time Do I fit this LOPT in No 1 or see what I could do with No2? I decided to fit another EY51 and change 3 caps around LOPT. Result a 2" high raster with a bit of video on it.

I now have 2 little projects on the go! SHMBO is not surprised she is just relieved its not another old car or bike.

Regards and thanks Steve.

[Heatercathodeshort]

Originally Posted by beltinge bore

I now have 2 little projects on the go! SHMBO is not surprised she is just relieved its not another old car or bike.

Well at least a PYE LV30 does not leave an oil stain on the kitchen table.

Not boring at all Steve. All part of the fun as a run through some of the wrecks that have been revived on this Forum will prove.
The stick rectifier can be any of the many types that were used in the late 1970's to replace the valve EHT rectifier, usually a DY802 [the modern EY51] in black and white TV's. The lack of height will sort itself out when you replace all [or most] of the capacitors in the frame oscillator/output stage. Do this one at a time and watch the frame open up. If you can scan the circuit, make a few copies and highlight the caps as you change them noting circuit positions and effect. You will learn a lot and it's a lot more fun than just replacing everything in one go and not really knowing what was causing the symptoms.
Sounds good so far. Good luck with it. Regards, John.

[beltinge bore]

Hello all I have changed waxy caps 2 at a time which resulted in a nice syncronised but rolling 2" testcard. I kept losing this and discovered a very loose intermittent tube base. This was changed for a Bush item and is now OK.

I cleaned the aquadag copper strips on the tube (got a bit of a "flash" off 1). The Raster was still small. At one stage along with sound clicks the raster expanded to almost full height then went small again. I gave up for the day.

Tried today. I now have total frame collapse. All frame pots seem to test OK. All cleaned with De Oxit. ECL80 Frame O/P Osc changed.Would I be right in thinking the frame and associated electrolytics should me my next job?

Regards Steve.

[Heatercathodeshort]

You need to check the voltages on the ECL80 valve. There should be reasonable H.T. on pin 1 the oscillator triode anode. If absent the blocking oscillator transformer may be O/C. Next are pins 6 anode and screen pin 7. Lack of voltage on pin 6 will denote an O/C frame output transformer. Check all relevant presets for continuity over their complete travel.
Ensure you have fitted correct value capacitors to the right tags. I think you have due to the height springing up. We can deal with the lack of frame sync [picture rolling up and down but not 'locking'] when you have a full scan. There should be at a guess around 10v on the ECL80 cathode with the output stage running. Pin 2. Leave the electrolytics for now. Well that's a start. Hope it helps. John.

[beltinge bore]

Thanks John I decided to mount the mains dropper properly as todays little job.

SHMBO is in for her annual romantic trip to the NVCF on Sunday followed by a trip to our old county Cornwall (Falmouth) for a week.Will report back when I return to the shed of lost hope next week.Kind regards Steve.

[Freya]

You could bring it with you, nice sunny Falmouth


Welcome to pop in..

Stephen

[beltinge bore]

Hello Steve We lived in Budock for 12 years my wife worked for Barclays in Truro until she got lucky with redundency.

Many thanks for your kind invite.Can I give you a call (number please) when I arrive (would love to see your Pye V4).

Regards Steven

P.S. i'm not as posh as you mine is spelt with a V.

[Freya]

Sending PM

[beltinge bore]

Had a quick look today . No HT on pin one ECL80 Applying and removing D/Mutimeter seems to make frame output try to start.Would frame osc blocking transformer be likely cause?

Regards Steve.

[Freya]

Sound like the transformer is open circuit, green spot failure

You may get lucky with a replacement, they do turn up from time to time. otherwise not to bad to rewind. Try Ed Dinning

[Heatercathodeshort]

A bit of a hold up but again solvable. It appears the LV30 was stored in damp conditions. At least you have a good tube and the makings of a worker. Almost any frame blocking transformer will work OK regardless of the actual resistances of the windings. Have a good week! Regards, John.

[beltinge bore]

Hello All

Back from sunny Cornwall to the shed of no hope!

Tested today using my trusty old AVO have HT on pin 1 of ECL80. HT on pin 6 (2 anodes I think) HT to pin 7 (screen). With the AVO set to AC I have 15 volts at pin 2. Applying the probe in this way gives me frame scan (at least 4")

HELP!

Regards Steve

[Freya]

One of your previous post says it expanded to full height and then collapsed again, it may be the control ? the wipers in them get fatigued.

Stephen

[beltinge bore]

Hello.

Changed Height & Frame Hold Pots (both tested all OK on AVO) still have no frame output.Waiting for 150K pot to arrive for Frame Linerity control.Old Pot tests dodgy on removal so hoping this is the problem.

Thanks for reading my boring missive Regards Steve.