Hacker Cavalier Loud Noise

[peter_sol]

Not a problem then.
Does the player work now martin apart from the occasional noise from the faulty valve?

[martinpinner]

With R6 re-soldered

Pin 2 is 0.85V Cathode of triode

and Pin 9 19.5V Anode of triode

whereas there was no reading before. When switched on it is making a hum with a crackling noise when turning the on/off and treble switches. I will try some more cleaner on the switches. It has been on for 5 mins and no loud noise yet. Am I safe to fit the deck to see if it plays a record.

[Nickthedentist]

Originally Posted by martinpinner

Am I safe to fit the deck to see if it plays a record.

It won't do any harm to try

[peter_sol]

I would say so yes
What make are the valves Martin?

[martinpinner]

Not sure of the make of the valves. Would have to remove to identify and do not want to remove yet. Will let you know. I did locate some valves at Chelmer valves should I require them. The cost was £38 for a pair including carriage. I think that is not a bad price. I will keep you informed on whether it plays a record but that may be tomorrow.

[Station X]

Originally Posted by martinpinner

With R6 re-soldered

Pin 2 is 0.85V Cathode of triode

and Pin 9 19.5V Anode of triode

whereas there was no reading before.

These readings don't look right to me even for a phase splitter. Anyone else care to comment?

[Station X]

Originally Posted by martinpinner

I presume that the "input plug" are the two spade connections.There is no difference in the reading whether plugged in or not.With regard to C15 I read on the circuit diagram that C15 is not required on the GP15ST. When checking R3 whilst turning vol/tone(player switched on) the resistance varies. Having done that the reading is now consistently 0.18mohms..

This makes no sense.

If C15 IS FITTED, then R3 should read close to 2.2M regardless of whether the plug is fitted or not and regardless of the positions of the controls. This is because C15 blocks DC.

If C15 IS NOT FITTED then the measured value of R3 should be close to 2.2M with the plug out, should change when the plug is in and should vary when the controls are rotated.

The plug in question would appear to have at least 4 pins. 1/PIN1, 1/PIN2, 1/PIN3 and 1/PIN4.

[peter_sol]

Pin 9 19.5V is low and we know it is not the valve so Martin now you can read the circuit diagram, check Valve holder 2 for wiring, soldering and correct components

[ms660]

Originally Posted by Station X

These readings don't look right to me even for a phase splitter. Anyone else care to comment?

Don't look right to me either, I'm looking at a schematic for the GP42, for all intents and purposes the same amp so far as I can gather, it quotes triode anode voltage of 145 volts (both triodes) 1.3 volts on one triode cathode and 1.2 volts on the other triode cathode.

Lawrence.

[Station X]

I'm glad you're in agreement because after all these posts I'm beginning to doubt my own reasoning.

The circuit for this player can be found way back attached to post #40.

[peter_sol]

Wouldn't we all like to look at this in front of us it can't be much
The joints to C7 and R7 on that tag at the top look dodgy
The best thing to do is re solder
Put iron on tag and feed solder on and let it flow until you have a good joint then remove the iron.

[Nickthedentist]

Originally Posted by Station X

The plug in question would appear to have at least 4 pins. 1/PIN1, 1/PIN2, 1/PIN3 and 1/PIN4.

Yes, plug 1 a 4-pin plug, whose mating socket is shown diagramatically at the bottom of the circuit digram in post 40 as "SKT 1."

It's attached to the short wiring loom which runs from the controls subchassis to the main amplifier chassis. In my example, the wires comprise of a cream-sheathed screeed cable, plus a yellow/white twisted pair.

[ms660]

Just an observation, picture in post#107, bottom tag strip 3rd tag in from left, something looks heavily pregnant to me?

Lawrence.

[martinpinner]

Suspect capacitor is a new replacement for C8. Located plug and will test again tomorrow.Attached photo that shows C1,C2 and C15.R2 has been replaced but I cannot seem to get an accurate reading of R1 which is 470Kohms.Readings fluctuate but level at 585kohms.This is a difficult one to replace.Will it be necessary? Will attempt to follow the circuit diagram for Valve 2.

[ms660]

Originally Posted by martinpinner

Suspect capacitor is a new replacement for C8. Located plug and will test again tomorrow.Attached photo that shows C1,C2 and C15.R2 has been replaced but I cannot seem to get an accurate reading of R1 which is 470Kohms.Readings fluctuate but level at 585kohms.This is a difficult one to replace.Will it be necessary? Will attempt to follow the circuit diagram for Valve 2.

RE: Post#193, I was referring to what appears to be under the tag.

Lawrence.

[Station X]

Originally Posted by martinpinner

Suspect capacitor is a new replacement for C8. Located plug and will test again tomorrow.Attached photo that shows C1,C2 and C15.R2 has been replaced but I cannot seem to get an accurate reading of R1 which is 470Kohms.Readings fluctuate but level at 585kohms.This is a difficult one to replace.Will it be necessary? Will attempt to follow the circuit diagram for Valve 2.

The vertically mounted 0.1uF cap on the left is C13. It's wired across the tone control RV3 and to the previously mentioned plug pins 1/PIN2 and 1/PIN3.

I'll hazard a guess that the pot with the resistor wired across it is RV2 and the resistor is R2 (220k).

The horizontal resistor is 470k, so that will be R1. The left hand horizontal cap looks like it's wired in parallel with R1, so it will be C1.

The other horizontal cap is C2.

I can see no evidence of C15 ever having been fitted, but checking R3 once the correct plug has been removed will prove that.

It may be difficult to measure R1 in circuit as it's shunted. I'd be inclined to leave it alone.

The thing to concentrate on is the low HT voltage on pin 9. R6 and R7 would be good starting points.

[peter_sol]

In post 193 it was mentioned about the 3rd tag from the left at the front has too much solder and it may be touching the metalwork.
Heat it up and let it drop off and solder it more neatly.

[peter_sol]

Martin if you read this carefully you will see that someone else has had the same problem with push pull valves in this case ECl82's
https://www.vintage-radio.net/forum/...ad.php?t=99448

[martinpinner]

Thanks for all info again. I assumed that the cap was C15 as I cannot see a C13 on the diagram. Also, it shows RV1&RV2 but not RV3.

The reading of R3 with the plug in is 0.18 mohms which varies when the controls are turned(power on) and 2.40 mohms with the plug removed which varies when the controls are turned(power on). I have checked the wiring of the valve pins against the circuit diagram and cannot see any issues. However, from the centre of the socket a wire is connected to both R3 and a wire from one of the tags at the back of the plug. Is this correct. I have made some of the joints better and took a reading on pin 9 and it was 80V.When turning the volume and treble I am getting some hiss/crackle but it is OK on the bass. Is this an issue just with the controls or wiring/components.

[martinpinner]

Thanks for the link regarding the valves. For information the valves are marked Made in England BVA.