PYE P28 radiogram no sound

[ZJS]

Hi,
I own a 1951 PYE P28 radiogram and just turned it on after years…
It all lights up as it should and the valves light up inside… the record player spins and it makes a low humming noise…
Power wise it is all fine…
However this is all it does…
I cannot get the radio to make any sound…
Just a low hum, not a crackle as you’d expect from a radio…
The record player was upgraded in 1974 to a garrard one… probably because the original only played 78s and the owner wanted to play their brand new Elvis records…! Haven’t been able to test the record player other than it spinning round which it does as the audio output wire on it is not currently connected to amplifier…

Im sure the amplifier works as when you turn the volume dial it makes the crackle noise through the speakers so the amplifier is amplifying the volume dials crackle…
I have plugged an Ariel into the Ariel port on the back but makes no difference…
When you turn the tuner dial the internal metal grill slat thing turns with it inside but has got a bit of a wobble to it… won’t make any difference as the wires are not affected or strained…
Cabinet is in good nick and there it has the original receipt… and also a bit of paper relating to it from 1999 so possibly worked then if someone put that in one of its draws at that time…

Any help much appreciated,

I can do very basic repairs but hoping it’s more of a simple problem…

 

[Bluejets]

With power off, give the volume and any tone or bass controls a good squirt of crc in where the termals exit as you rotate the knobs.
Could be twin pots depending on whether mono or stereo system.
Check all electrolytic capacitors for signs of bulging or leakage.
Firther checks will require knowledge of valve operation and ability to work within the high voltage dc range of 300 volts.

 

[Bluejets]

Note that valve sockets can get grubby as well requiring similar treatment as the pots with crc.

 

[73's de Edd]

Sir ZJS . . . . . . . . haven't our paths crossed before in the past ?

I see your updated turntable below, but you must have used different routing on the phono cartridge audio input into the radio.
Look a the photo below and see the right side terminal blocks plug in connections (LS) to the units speaker.
At far left is Pu marked as being the "Gramophone" audio inputs to the unit.
Of your frontal knobs, confirm if there is being a phono input switch setting.

As your situation stands . . . . with no radio sound and no phono sound . . . . we don't know if you have a loss of B+ supply voltage to a portion of the set.
For starters turn the radio on and set up as usually used in the phono position, turn the volume to max and then reach down and GENTLY finger tip stroke the stylus end. That amplified scratch would confirm that the audio portion of the unit is working for you.

SURMISAL . . .

If there are being only 4 knobs across the front of that unit, looks like the second from left would be THE knob of our interest.

I read k . . c . . a . . b, and ten saw your comment of the phono output not being connected into the radio . . . . are its existing plugs being banana jack connectors . . . . that will let you plug into that PU input ?
The top PU connection is audio in and the bottom one is its ground connection.

Waiting . . . . . .







73's de Edd . . . . .

 

[ZJS]

Thank you for this, I am a hoarder of old radiograms… I’ve had most of them for a few years now and they are just breaking down… leaving me scratching my head on what to do as I only really know how to repair the mechanisms.

It seems the turntable hasn’t ever been fully connected, it has power which someone has done very neatly, but no audio connected. There is just a wire with a 70s 5 pin din plug on the end of it.
I am scratching my head on how to join that to 2 banana plugs… I was thinking to join all the coloured wires together and join them to the red banana plug and turn all the sheath to the black banana plug…?
My first initial response was, “I must put a record on it to see if the record comes through speakers” but then realised that it wasn’t connected.
Thanks

 

[73's de Edd]

Sir ZJS . . . . .
Do a re read of the end of my last post, as I think I might have added some final info onto it.

A much simpler test of the audio section . . . . . . considering that carpeting or any isulative floor covering is present.
(THUSLY . . . . that you are not standing buck naked and barefooted on a concrete or dirt floor in some 113th world country.)

IS . . . .to make full use of that " Salty Corpus Delecti" of yours, and its capability of picking up spatially radiated 50/60 cycle from house wiring.

Now Do this . . . .
Take a small blade metal screwdriver in hand and initially make your thumb and index fingers more effectively conductive by wetting them with some spittle so that when you re grip ONTO the metal blade of that screwdriver . . . and not onto its insulative handle.
You are then going to be a feeble hummmmmmmm audio signal source.
BRACE YOURSELF . . . . . as when you touch that blade tip to that TOP . . . . PU input . . . . . connection . . . . initially expect a pop from any additional static electricity discharge and then a constant level of hummmmmmmm from HUNDREDS OF THOUSAND microvolts of picked up radiated AC wiring fields.
That confirmed, about half of your radio circuitry is working and being fed B+ from its power supply..
Thaaaasssit . . . .

73's de Edd . . . . .

.
Report

​

 

[ZJS]

Hi,
Thanks for getting back to me…
I’ll wire up the turntable as soon as I can and do the initial test… hopefully it works audio wise as the turntable is what I want to work the most, only one MW channel left in the uk which is that sport channel,
I’ll join all the coloured insulated wires in the 5 pin din wire to the red banana plug and then all the sheath to the black banana plug… done this in the past and worked…
All the best

 

[ZJS]

Hello, wired up the turntable today bu connecting the 4 coloured insulated wires to the red banana plug and all the sheath to the black banana plug.
Turned it on. Nothing. Still the same old hum. I got my index finger like you said and rubbed the stylus but absolutely nothing. Even put a record on but still nothing.
Must be more than a minor problem..?
What would you do next.?
Thanks

 

[73's de Edd]

Do the NOW DO THIS test, since you made no mention of your having done it. With confirmation being, that the top left corner PU connection is being the " HOT " audio input and its bottom left corner . . . . is its ground connection.

 

[ZJS]

When I do that should I expect a hum coming from the speaker or from inside the gram???

 

[ZJS]

I’ll do the test now

 

[ZJS]

when I scratch the banana plug on to the port it needs to go in it makes the same scratching noise out of the speaker

 

[ZJS]

Did the test you said to do but with a electric screwdriver with a little light in it…
When I stuck that in it and put my finger on the end of the screwdriver (has a little metal circle which you put your finger on it to enable the light to come on)
The light very very very dimly lit up and I heard a little buzz come from the speaker… when I took my finger off the end of the screw driver the dim light went out and the buzz stopped… I tapped the end and the light flickered and the buzz flickered…
Thought I’d do it this way as a bit safer (couldn’t bring myself round to touching the un insulated screwdriver…)

 

[73's de Edd]

When I do that should I expect a hum coming from the speaker.
The amplified 50~ hummmmmm will be coming from the speaker.

You totally confused me with that electric screwdriver . . . .
Why is its work lite lamp dim . . . . . . . is it just due to its long time inactivity and weak batteries ?

I tapped the end . . .? the screwdriver end ?
(I couldn’t bring myself round to touching the un insulated screwdriver…)

DON'T WURRY 'BOUT ITS !

That is a transformer powered . . . . . right rear corner of chassis + it is massive . . . . . therefore it is an AC power line isolated set.
Also that top PU connection goes into a coupling capacitor . . . thus providing DC isolation and absolutely no line ac voltage is on the other side of that cap.
Now do it again . . . . . as was prescribed . . . . . and the wetted conduction enhancing spittle is being important.
Do it . . . . . DO IT . . . . . DO IT . . . . . DO IT ! . . . . . . (to it)


73's de Edd . . . . .

 

[ZJS]

I have just brought myself round to doing it like you said… exact same outcome - little buzz through speakers.
When I move it around the buzz seems to slightly change tone…
Thanks
Zach

 

[ZJS]

I say speakers in my last post - I should have said speaker as it’s only got one…

 

[73's de Edd]

That's Great . . . .
It's strange that having connected the audio out of the turntable and gently finger stroking that cartridges needle tip didn't give you oodles more of "audio" during that test . . . . . UNLESS the cartridge is dead.

Next logical . . . .more confirming test . . . considering what you might already have found out.
That being the use of another audio input source . . . with that audio being an old generation Beta or MOST likely, VHS player.
Or a music CD player or video player the likes of which output their audio thru RCA connectors and attached cables.
Get whichever of these that you might have and a tape or CD or DVD materiel source .
Power up the PYE and warm up, be sure its switched to PU audio input..
Start the opted audio signal source playing.
Take a long enough RCA double male patch cord and then plug one end into one . . . .R or L . . . . of the audio output jacks and take the cables other free end and clip lead connect / OR / loop a length of bared hook up wire around that RCA outer shell and twist tight onto the outer ground shell. Then hold the protruding central signal connector nib of that RCA connector into contact with the top "HOT" PU connector while you manipulate the earlier affixed ground wire to the bottom PU connector.
If your radio volume is maxxed up . . . . . . I hope that you will finally have some good level of that fed in audio.
Meaning . . .that the radios power supply and all of its audio circuitry being fed by it is functioning.
Its just now leaving a suggested fault with the two tubes on the left and their associated circuitry.
And . . . . . ALAS . . . . . I can find no FREEBIE schematic for this PYE P28.

73's de Edd . . . . .

 

[Bluejets]

It's strange that having connected the audio out of the turntable and gently finger stroking that cartridges needle tip didn't give you oodles more of "audio" during that test . . . . . UNLESS the cartridge is dead.

.............. or the volume is set too low.

 

[ZJS]

Hi, yes one of the tubes seems to be not lighting up but it’s a strange looking one with a metal thing inside of it… does get quite hot inside due to other valves lighting up… so some are working???
I have a garrard SP25 which has 2 red white plug outputs. I plugged the red one in the red pu socket and the white one in the black pu socket.
Same outcome. Although this SP25 doesn’t have a cartridge… but I did get a screwdriver and prod about the socket in which the cartridge plugs into.
Maybe I should try something else with it…
You say two of the valves have got.
Now my heart sunk when you said that as I know valves can often cost a fortune and impossible to find…

You said about the schematic…
I do have the original owners receipt with the unit with lots of dates and costs written in it about details… would this help you find one…?
Thanks

 

[ZJS]

I have some old valves which I could try?