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Help re A Pye FV1?

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Kevin19
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Hello to everyone.

A few years ago I dabbled in restoring a few older  Pye TV sets and had great fun and had so much kind help from the various place on the Internet when I got stuck particularly on my rather Lovely Pye Bakelite V2 and my Pye BV20C Sets which still work so well today.
But like I say that was years ago In these lockdown days I thought it may be fun to have a go again at another one of my none working Pye sets. So this brings me on to my Pye FV1. I have read about drying the LOPT out which I have followed before even starting to attempt any restoration. Now the Tube gave me good emission on my CRT Tester the power resistors had totally disintegrated so after sorting those out and then one by one changing the many capacitors in this set I reach this point. I enclose a photo of what I have on the screen now I have connected up the Aurora but don't seem to get any signal going thought the set as this is all I get on the screen being somewhat rusty after the years not doing any old TV work so I have lost the plot a little to the ways of old TV's and not wanting to rush in and start changing this and that. So I wonder does anyone have any ideas to where I should look next on this Pye FV1 I'm no expert so please do bear that in mind, please! I was just so pleased just to get a raster up on the screen! But any thoughts or ideas would be very welcome indeed how to move on Picture below to what I get on the screen. My thanks Kev.

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Topic starter Posted : 06/05/2020 6:00 pm
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crustytv
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Hi Kev, welcome to the forum.

As this is a Band I (1,2,3,4,5) have you set the three screws next to the aerial for the TV channel? Have you set the Aurora accordingly?

pyefv1

Do you have any indication of a test tone coming from the Aurora? The photo makes me think IF fault (no vision/sound or perhaps both). In which case it might be worth checking V1(EF80), V2(ECL80) are seated OK, though its never that easy is it, valves are pretty much bullet proof, bound to be more going on.

Do you have the PYE service manual?

This general B&W TV repair guide might also help refresh you, see here

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Posted : 06/05/2020 6:32 pm
Nuvistor
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If you have scope, check the line and frame speed, the line down the screen could be line off frequency or the line drive control mis adjusted.
Check voltages.
Use a scope and sig gen to trace a signal through the IF to video and sound output.

Confirm the channel the set is tuned to is the same as your Aurora.

Something to start with but of course there are many ways to fault find.

 

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Posted : 06/05/2020 6:38 pm
Kevin19
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@crustytv

Many thanks, yep screws all in line and set right with Aurora. Yes, I have all the service data possible even the 30 pages of Pye's own FV1 data. Sorry, no scope or therefore would not really know how to use one! Both Valve 1 and valve 2 have been replaced with good known ones no better same raster as picture very very slight sound. I have tried to naturally to gently adjust all the controls including the line drive with no effect on the screen. Thanks, I will perceiver on if I have a little free time tomorrow but thanks for both of your thoughts it's so good to get someone else views and take. Many thanks, Kev.  

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Topic starter Posted : 06/05/2020 7:13 pm
Jayceebee
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Hi and welcome from me too. When you say you have slight sound do you mean you can hear the test tone of the Aurora or just noise?

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Posted : 06/05/2020 7:38 pm
PYE625
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Hi Kev, one thing that may be a possibility is that if the fine tuner is set too far out of adjustment, the channel selectors might not correspond to the actual channel the set may be tuned to. It might be worth adjusting the set for say CH3 and switch the Aurora either side of CH3. Then adjust the fine tuner to see if there are any results, or repeat it with other channels selected and just switch through with the Aurora. Set the vision sensitivity and volume to maximum, but keep the brightness so a raster is just visible.

On a seperate note, I would try and set the line drive control (C33A) to a minimum or to try and get that vertical line to go away. It won't do the set any good if overdriving the line stage, hopefully the manual will say where best to adjust it to. This naturally assumes that the vertical line is being caused by incorrect setting of C33A, it is only a possibility to be aware of.

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Posted : 06/05/2020 7:44 pm
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crustytv
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Should other members also wish to dip in and offer some assistance to help kev, the PYE FV1 service manual is in the data library. ? 

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Posted : 06/05/2020 7:52 pm
Till Eulenspiegel
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I might be able to help you with the FV1, my set has been in my possession since 1960. 

It was quite common for the vision sensitivity control to go open circuit, R31A in the Pye service manual. Same goes for the contrast control, SM ref. R14A. Make sure the RF amplifier (EF80) and the frequency changer (ECL80) valves are in the correct positions. The local oscillator feed resistor can go open circuit or high value, SM ref. R12A 22Kohms.

It's most likely the Hunts make decoupling capacitors in the IF unit will need replacing, failure of these is known to give very low gain from the IF amplifiers. The cross-over kink on the raster can the result of the line oscillator is running too slow, check R55A 33Kohms and R44B 100Kohms. Check the adjustment of the line drive trimmer after the line timebase is running at the correct frequency, 10,125c/s. Replace the coupling capacitor between the line oscillator and the grid of the PL38 line output valve, SM ref. C34A, (0.01mfd). 

Till Eulenspiegel.

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Posted : 06/05/2020 8:21 pm
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Kevin19
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@pye625 Thanks I just quickly had a go and adjusted  (C33A)  as far as it would go and I have lost the line now! So that's a start not had time this evening to try other things as yet but thanks for that. Kev.

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Topic starter Posted : 06/05/2020 8:27 pm
Kevin19
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@till Hi thanks Yep both the contrast and that vision sensitivity control seems to do little or nothing to the raster on-screen, so I had wondered and must check these as they could well be duff for sure. I had noted they say this in the Pye service data as you said. I have carefully changed many of those horrid little caps in the iF unit but may well have missed some will go back and check also check the resistors you say about thanks that is such a great help for me and a good starting point to work on thanks to everyone for there kind help! Will keep you posted to how it goes what I find. Kev.  

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Topic starter Posted : 06/05/2020 8:34 pm
Till Eulenspiegel
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Interesting to note that in the Pye FV series of TV receivers the intermediate frequencies are almost near the BREMA values being 35.5Mc/s vision and 38Mc/s sound. BREMA 34.65Mc/s and 38.15Mc/s. 

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Posted : 06/05/2020 8:44 pm
PYE625
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Posted by: @till

The cross-over kink on the raster can be the result of the line oscillator running too slow, check R55A 33Kohms and R44B 100Kohms. Check the adjustment of the line drive trimmer after the line timebase is running at the correct frequency,

That is very good advice and a rather crude method to roughly set the line speed, if no other method is available, is to listen to another set running correctly and simply adjust the FV1 line hold for a near approximation of whistle pitch. At least this way, you will get the line hold nearer to the right frequency. ? 

Like I say, crude, but it will help ensure the line stage is not in any great pain while you get the rest of the set up and running and tuned in to a signal.

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Posted : 06/05/2020 9:48 pm
Katie Bush
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@pye625

Funnily enough, I was thinking much the same thing! ✅

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Posted : 06/05/2020 10:08 pm
Kevin19
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@pye625 Many thanks that's given me so much help and I now have loads of things to follow up on I just drew a blank where or what to do next so thanks to everyone for there so helpful advice. I will report back in time to how it goes thanks again to you all. Kev.

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Topic starter Posted : 06/05/2020 11:11 pm
Kevin19
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Well Hi to everyone again.

 
 Pye FV1 Update. Well, a bit of a disappointing afternoon on the Pye FV1 again. So first I checked the Contrast Control (R14A) which is OK. Then checked the Vision Sensitivity Control (R31A) also fine. Then moved on to the Local Osilator Feed  Resistor (R12A) 22k This was fine in limits. Then Replaced  (R55A) 39k  and also replaced (R44B) 150k All capacitors have been replaced in the RF side the many small Hunts that lurk in there had a good check all around to see all valves in right location yes they were. Switch on still the same as before well worse as the line down the centre is even brighter and I can't lose it now! O, dear! Switch set off lift chassis up and a little bit drops out it appears  V3A vision the CG5C has disintegrated the little plastic centre has broken away from the two ends which are still soldered in so that is now duff! Is it possible to put any replacement part in there?  Decided to have a good look around the rest of the set. I unscrew the pannel re the Line Amplitude  L18 and Line Linearity L17A  to fined it looks like L19 bottom (which does not have a slider) is broken as it has lost its rubber cap holding into the bracket and the adjustment rod has gone I assume it should have one inside the small tube so you can move this up or down say? Other than that it has beaten me again to this point in time like I say the raster seems brighter but so does the white line down the screen which I could not get rid of so did not run the set long. O well, I'm not going to give up yet for sure. Kev.
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Topic starter Posted : 07/05/2020 10:19 pm
crustytv
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Posted by: @kevin19

CG5C has disintegrated the little plastic centre has broken away from the two ends which are still soldered in so that is now duff! Is it possible to put any replacement part in there?

As you've discovered that's the vision detector diode, that'll explain a lot. What diodes do you have in stock? Try an OA90/91 or failing that a 1N4148 if you have some. Might be worth replacing V3B (sound detector diode) whilst you're at it, it's the same type as V3A and probably dodgy as well.

Still, its all good progress, you've found a few things to address, keep up the great work, we look forward to your next update. ? 

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Posted : 07/05/2020 10:32 pm
Kevin19
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@crustytv Thanks yep this evening I did solder an OA90 in both vision and sound as I used these in my Pye V2 from memory! But sadly no difference re-screen! Kev.

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Topic starter Posted : 07/05/2020 10:55 pm
PYE625
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Did you try the diodes both ways round, only I have been caught out before.... losing track of the correct polarity.

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Posted : 08/05/2020 10:03 am
Till Eulenspiegel
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Confirm that the local oscillator is active by measuring the negative potential between the grid and cathode of the ECL80 triode section. The grid resistor R2B will be a convenient test point.

Connect a resistor of at least 68Kohms in series with the test lead otherwise a direct connection to the triode grid will damp the oscillator.  In this receiver the local oscillator operates above the carrier frequencies. For channel B1 reception the local oscillator frequency is 79.5mc/s. Have you replaced or checked the ECL80 cathode bypass capacitor C4G? Failure of this component will stop the oscillator working.

The HT to the receiver circuits comes direct from the smoothing capacitor, no sub HT rails.

Till Eulenspiegel.

fv1snip
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Posted : 08/05/2020 11:03 am
sideband
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Well that's the first time I've seen an ECL80 used as a frequency changer.....one wonders what the logic was behind that! I was about to suggest that the wrong valve had been fitted and it should be a PCF80....just as well you showed the circuit!

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Posted : 08/05/2020 12:48 pm
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