Hacker Cavalier problem with sound

[sparkymike]

My daughter brought me over a Hacker Cavalier record player for me to look at and check over. Very clean case, been in a cupboard for many years I guess.
The Garrard Autoslim would not work automatically and record would not reject at end of tracks. I removed the turntable and founf that the small lever on the side of the geared cam was seized solid. After freeing off, all good now in that area. Problem now is bad distortion on sound which gets worse as volume is turned up. Any thoughts here welcome. Later today I will remove each of the output valves in turn and see if it improves.
Mike.

[sparkymike]

One thing I should mention, treble and bass are both not functioning no matter where knobs are turned. The turntable mat has disintegrated, seems to be made from thin chocolate !!
I think I have a spare rubber one in the loft which may fit.
Mike.

[Edward Huggins]

Sounds like a power supply problem/voltage starvation. Could be a deteriorating cartridge, but suspect PSU. If you have a circuit diagram, start measuring voltages after the cathode of the EZ80.

[vinrads]

Hi Mike whenever I am called to repair one of these I always replace the anode feed resistors 220kohm also I think 820k ohm these are carbon even if the would read ok they can cause noise, use the modern metal film type also replace the g1 coupling caps unless they are of the mustard Mullard type ,also there may be a few wax capacitors around the tone control cct . a pic of the amp would be helpful. Mick.

[sparkymike]

I think my best bet is to first inject a music source( ie my Leak tuner) into the volume control and then see if there is still heavy distortion. This should prove if the cartridge is faulty or if it is the amplifier at fault.
Mike.

[David G4EBT]

There's a video here of diagnosis and repair of the electronics on a Hacker Cavalier GP15 which might be of interest:

https://www.google.com/search?q=hacker+cavalier+record+playe...d=cid:9fc44b34,vid:DVjYZdz7H0w,st:0

The accent of the restorer ('Vintage guitar Amp Repairs & Online Guitar Teacher') sounds like a Notts, Derby, Leics - I'd guess north Notts, but tends to use American terms - 'tubes, schematic, plate voltage' etc, rather than 'valves, circuit, anode', not that it matters. (Someone might know him?). It looks like long-departed woodworm have been up to mischief here and there, though not visible externally. (Dog gets in on the act in the final minute or two!)

Good luck in sorting it Mike.

[sparkymike]

Thanks for that video, very useful info there and this one sounds exactly like that one did before he changed all the components. Luckily this one does not look to have the woodworm problem yet and was clean as a whistle under the deck with no dust at all, which is unusual on any of these old sets.
There was an add-on amplifier and speaker available for this player so you could then have stereo and my guess is they were used a lot in schools.
Mike.

[sparkymike]

Anyone any idea what the voltage would be on the main smoothing/reservoir cap ? The very large 3 ? watt resistor is reading very high so will change that for a start. No sign of any Hunts capacitors only TCC which could be a help.
Mike.

[sparkymike]

I am looking for the circuit for this recordplayer. At the moment only found half of the circuit on an old post on this forum.
Mike.

[Nickthedentist]

Its here:
https://www.radiomuseum.org/r/hacker_cavalier_gp15.html

Click the Schematics tab, click on the circuit diagram, then you're allowed a free download even if you're not a member. It will be sent to your e-mail address.

Mods... this is NOT available from Paul BTW.

[sparkymike]

Thanks I will try that. I did look on Paul's list. Surprised it was not on there.
I would think that the same circuit was also used for the add-on amplifier/speaker box. I found that the large 3watt resistor was double its marked value so have ordered another one. I am having a quick look in between building work. Voltage on the large .05uf capacitors on the output valves was 47 on one and 12 on the other , so something wrong there. I will change those caps anyway.
Mike.

[sparkymike]

Photo of the amplifier . Neat wiring and most parts easy to get to.
Someone had been there before as the hold down plates and 4ba nuts were not in place as intended. A mystery piece of plastic was tucked down next to the mains transformer. What is it ? Part of the record player ? There are some drops of wax under the mains transformer. Maybe got very hot sometime in the past. I will have to check all output voltages. A remarkably clean interior, unless previous person who went in gave it a dust.
Mike.

[Paul_RK]

Originally Posted by sparkymike

A mystery piece of plastic was tucked down next to the mains transformer. What is it ? Part of the record player ?

Looks like a stylus guard, I'm not sure if the 9TAHC itself could have been supplied with some later Cavaliers or whether it's from a different cartridge.

https://www.gettheneedle.co.uk/sonotone-9ta-hc-stereo-ceramic-cartridge-lp/33/45.html

Paul

[thermionic]

Those ‘Supamold’ capacitors will need changing, along with the 4, red electrolytics, in addition to the resistors already mentioned.

The ECL86’s will need to be treated carefully……. Not a cheap commodity these days!

These are well built, high quality players, and I have a bit of a soft spot for them.

Good luck with your restoration.


SimonT.

[sparkymike]

I knew I had seen one of those bits before long ago in the past. I reckon you are right . Mike.

[sparkymike]

I have now changed C6 and C7, the .05uf capacitors on the grids of the two output valves as originals were shot. I have also changed the 3 watt 1.5K resistor as it was reading over 2k. Glad to say that distortion has gone now and noted that it has quite some volume if required. Mains transformer is now running a lot cooler. I am thinking that the leaking caps may have been drawing too much power from the transformer which would account for the drips of wax I found on the case under the transformer. This must have occured many years ago as it looks to have been tucked away in a cupboard for many years.
Only small point now is that the tone control does not seem to make much difference but bass control is fine.I will have to check components around that area which are on a small board fixed to the side of the cabinet.
Thanks for all advice above.

[Ed_Dinning]

Try small caps located in the treble control circuit

Ed

[Boulevardier]

Whatever else you do or don't do, If you haven't already done so, I'd strongly advise you to replace those 0.05 microF capacitors feeding the control grids of the ECL86s. Those valves don't like it up 'em, and they aren't cheap nowadays. Also, check for overheating of the O/P transformers.
Mike

[sparkymike]

Hi Mike, read post two up. Changed those caps that you are talking about. They were causing the distortion and more.
Mike.

[Boulevardier]

Ah, OK. I hadn't clocked your previous mention- and the cap. numbers on the Radiomuseum schematic are illegible.
Mike