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Old 1st May 2017, 4:36 pm   #1
G0HFCFrank
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Default Pye PE60

Hi Folks,

I found time to investigate a Pye PE60 over the weekend, I had bought it on a general flea market a couple of weeks previously. I first cut out the caps across the mains supply (C72 & C73) the replaced 'that cap' C63. powering through a lamp limiter and measuring voltages, the anode of the audio triode V4 went down from 85v to 40v as I turned up the volume control. Replacing C53 & C54 fixed that.
Still nothing out of the set so measuring valve voltages showed G2 of V1 V2 & V3 all at 200V+ instead of the 90V on the trader Sheet. Are my valves low emission or am I missing something?

Help please,

Frank C.
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Old 1st May 2017, 11:30 pm   #2
Wellington
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Thumbs up Re: Pye PE60

Quote:
Originally Posted by G0HFCFrank View Post
Still nothing out of the set so measuring valve voltages showed G2 of V1 V2 & V3 all at 200V+ instead of the 90V on the trader Sheet. Are my valves low emission or am I missing something?
Hi Frank

Looking at the Radio & Television Servicing (R&TVS) sheet for this set (off Paul's CD), the screen grids of V1, V2 and V3 are fed from the same point, so I'd be inclined to suspect a HT supply issue rather than all three valves. The component numbers you quote match those on the R&TVS sheet so I think we're referring to the same circuit.

The high screen voltages you are seeing combined with the lack of sound suggests that there might be a problem in the output stage. For example, if the primary of the output transformer is open circuit, the output valve won't be drawing any current and the HT may be higher than it should be.

Measure the voltages at the cathode of the rectifier (should be DC 270V, according to the sheet) and the anode of the output valve (255V) and that might give us a clue as to what's going on…
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Old 2nd May 2017, 5:38 pm   #3
G0HFCFrank
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Default Re: Pye PE60

Hi Wellington,
The HVs look good, 270v on the rectifier cathode and around 250/255 on the OP valve anode and screen. Despite a rustling in the speaker when touching the volume control I found the OP valve cathode to be only 1.2v substituting another EL41 brought this up to 3.8v and the rustling was louder. the common screen supply to the first three valves is still way high and I can only think this is because no screen current is being drawn? with the better OP valve the lamp limiter lit a bit brighter and I found 185ac on the mains input. Pulling the OP valve dimmed the bulb considerably and the mains input went to about 225ac. I'm tempted to ditch the lamp limiter altogether and listen for the bang. What do you suggest?
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Old 2nd May 2017, 7:04 pm   #4
Boater Sam
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Default Re: Pye PE60

You can't get proper voltage readings with it under powered on the lamp limiter. The valves aren't conducting fully due to the low voltage. So it won't work! The HT looks good because you are not drawing enough current.
Give it the beans and check all the valve voltages, the cathode to chassis on the output valve should be at least 6v with the 330 ohm bias resistor.
Nice radios, if you ignore all the band switching it is a very ordinary 5 valve superhet, like a Bush DAC90A but with a proper mains transformer.

Last edited by Boater Sam; 2nd May 2017 at 7:05 pm. Reason: addition
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Old 2nd May 2017, 7:31 pm   #5
Wellington
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Default Re: Pye PE60

D'oh - I'd forgotten about the lamp limiter.
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Old 2nd May 2017, 8:03 pm   #6
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Default Re: Pye PE60

Frank,

Just out of interest, which PE60 do you have, the six valve version or the six plus EM34?

Andrew
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Old 11th May 2017, 8:18 pm   #7
G0HFCFrank
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Default Re: Pye PE60

Andrew,
My PE60 has six valves plus EM34 and has a 12 position wavechange switch with Long Wave included.

Everyone,
I have been away from my shed this week but have been studying the circuit diagrams and I just do not understand how to read the wavechange switch. Are the segments alternately labelled FRONT & REAR to be read clockwise and counter-clock? how are the contacts made? For instance I am totally baffled by switch section S1P, it appears to connect the gram input to the oscillator grid. The connections to that switch could be related to a clock face and labelled 1,2,3,4,5,7,8(NC),9,10 & 11. Does the 'eyebrow' connecting 11 to 1 rotate? similarly does the 'mouth' connecting 3,4,5,7 & 9 rotate? Why is the common cathode line of V1 V2 & V3 in there. Please someone, save my sanity.

Frank C.
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Old 12th May 2017, 8:21 am   #8
ms660
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Default Re: Pye PE60

I haven't got the schematic for the PE60 but I have one for the PE80, in that one the triode oscillator section of the ECH42 is used as the 1st audio amplifier when switched to Gram, when in waveband (radio) mode the triode's grid resistor is 47k, when in Gram mode it is, in effect, 314k.

"Does the 'eyebrow' connecting 11 to 1 rotate? similarly does the 'mouth' connecting 3,4,5,7 & 9 rotate? Why is the common cathode line of V1 V2 & V3 in there. Please someone, save my sanity."

So far as I can make out they do rotate and I think they maybe shown in the fully anti clockwise position which is the Gram position, one "click" clockwise to a waveband position and you should be able to see how the extra grid resistors mentioned above are now bypassed to chassis thus making the grid resistor 47k which is what is required when in a waveband position for the oscillators grid resistor.

If that makes any sense.

Lawrence.

Last edited by ms660; 12th May 2017 at 8:34 am.
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Old 12th May 2017, 9:32 pm   #9
Wellington
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Default Re: Pye PE60

Hi Frank

The switching on this set is rather confusing, though I suppose that's to be expected as it has LW, MW, nine SW bands and GRAM!

My reference (which is the Pye Service Sheet for Model "H" Type PE60V - as included on Release 1.0 of Paul's DVD) has the following notes:
  • "All switches shown in fully anti-clockwise position."
  • "Wavechange switch in "GRAM" position as viewed from the rear, i.e. the anti-clockwise rotation indicated on the circuit represents a clockwise rotation in the receiver"
(I do find that second one rather confusing).

Anyhow, for what it's worth, I've attached a snippet from the circuit diagram of switch S1P so we can see the subject under discussion.

Click image for larger version

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Overall, I concur with Lawrence - the triode section of the ECH42 (V2) appears to be used as the first audio amplifier when the wavechange switch is in the GRAM position.

To address some of your questions individually:

Quote:
Originally Posted by G0HFCFrank View Post
Does the 'eyebrow' connecting 11 to 1 rotate?
Yes.
Quote:
similarly does the 'mouth' connecting 3,4,5,7 & 9 rotate?
Yes.
Quote:
Why is the common cathode line of V1 V2 & V3 in there
Not sure. I suspect it may be altering the grid bias on valves 1,2 and 3 to turn them 'off', thus saving power when the set is being used in the 'Gram' position. That's essentially a guess, though.
Does your Trader sheet not give a description? They're usually pretty good at explaining the circuit.
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