Ekco RP364

[bobbyball]

On the RC209/210 changers the detection of "no more records" on the stacking spindle is by the "feeler" arm, the overarm being there to merely steady the records. The whole mechanism is very complex and it will be some part still "sticking".

[Nickthedentist]

Have a look here, particulary p.17:
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&c...39-vjvNyYnyEy3JNokIyII&opi=89978449

[DonaldStott]

I’ve been inactive for many months (medical reasons) so my brain is a bit addled - remind me, how do I remove the striker cam to gain access to lubricate the thrust washers and ball bearings?

[DonaldStott]

Eventually located the two screws that hold the striker cam assembly to the shaft!

I have memories from a previous Garrard 210 restoration that the ball bearings are loose and fall out when disassembled. Fortunately I bought a bag of spares just in case.

Auto-changer mechanism still a bit slow and sticky at the start and end of the cycle so, as expected, the culprit is probably the idler wheel despite trying all the usual ‘fixes’.

[DonaldStott]

Tried all the standard methods to improve the torque applied to the auto-changer mechanism but has anyone attempted to slightly reduce the length of the Idler Wheel Tension Spring: -



My only concern would be any impact on the motor bearings as a consequence?

[DonaldStott]

While still experimenting with options to 'fix' the idler wheel problems in the Garrard R209 auto-changer I've moved on to deal with the electronics in the Ekco Model RP364.

The large dual can capacitors (C2 and C3) will be re-stuffed with 47µF 450V electrolytics but I note that many others physically resemble bipolar capacitors, for example, here are C1 and C9: -



These have red and black end caps and I have no reason to believe that bipolar capacitors are required as replacements in these locations?

Here is a section of the schematic showing C1 connected to the V1A triode cathode of one of the ECL82 valves:-

[Nuvistor]

Those TCC capacitors are standard electrolytics, replace with 47ufd 25vw.
Looking at the circuit, check C5 for leakage or it could damage items in the output stage.

[vidjoman]

The capacitor that you ringed in red shows the positive (open box) and the negative as a closed (black) box. Usually the symbols on most diagrams for an electrolytic.

[David G4EBT]

Originally Posted by Nuvistor

Those TCC capacitors are standard electrolytics, replace with 47ufd 25vw.
Looking at the circuit, check C5 for leakage or it could damage items in the output stage.

Likewise C8, given that there are two identical amplifiers/output stages on the printed circuit board - each using a triode/pentode ECL82.

V1 for the LH channel, V2 for RH, each feeding matching speakers - one in the cabinet - the other in the lid.

[David G4EBT]

Originally Posted by DonaldStott

While still experimenting with options to 'fix' the idler wheel problems in the Garrard R209 auto-changer I've moved on to deal with the electronics in the Ekco Model RP364.

The large dual can capacitors (C2 and C3) will be re-stuffed with 47µF 450V electrolytics but I note that many others physically resemble bipolar capacitors, for example, here are C1 and C9: -

Attachment 320509

These have red and black end caps and I have no reason to believe that bipolar capacitors are required as replacements in these locations?

Here is a section of the schematic showing C1 connected to the V1A triode cathode of one of the ECL82 valves:-

Attachment 320510

C1 and C9 are the cathode bypass capacitors for the triode (driver) stages of the two valves, both 50uF [47uF] 25V electrolytics. As they're mounted vertically on the PCB, they'll need to be radial rather than axial. Likewise, C7 & C10, both 25uF [22uF] 25V are the electrolytic cathode bypass capacitors for the pentode (output) stages of V1 & V2. Again, vertically mounted on the PCB, so radial rather than axial.

As to the twin reservoir (C3) and smoothing cap (C2) in one can, to provide HT1 (252V) there is a further smoothing cap for HT2 (212V): C6 (16uF), again vertically mounted so needs to be radial.

Hopefully the selenium bridge rectifier will still be poking out 250V DC.

Looks a nice record player - a cut above some of the Dansettes with a single valve and a component count so low that it looks like they designed a amp that worked well, then kept removing components one at a time till it stopped working, then put the last part back in! Quite novel that the detachable lid with speaker could be suitably positioned away from the cabinet to give a stereo effect.

Every success with it.

[DonaldStott]

Thanks to everyone for their clarification and additional information regarding the electrolytics in this record player.

As usual there are some that have values that are not really standard these days e.g. 25uF, so do I go up to 33uF or slightly down to 22uF, both widely available?

There are also two 500pF Hunts capacitors (!) strapped across the Tone controls (RV2A and RV2B - both 1M) but these seem to be rated at 600V DC! I can’t find such matching values anywhere and really not sure why there is a need for 600V DC at this location?

[smiler411]

You may be better looking for 470pF and 630V or 1000V these should be available from a few sellers as they are more standard modern values. They would be fine I should think. Suppose should be film type but doubt that a ceramic would make too much noticeable difference.

The high voltage may be because the capacitors are connected to the output transformers and peak voltages much higher than the HT will be found there.

[Simon Gittins]

I use 22uF as a replacement for 25uF, there is a wide tolerance for electrolytic capacitor values anyway. I can't see a problem with using 33uF though.

[DonaldStott]

0.47nF 1kV ceramic capacitors on Order along with both 22uF and 33uF electrolytics.

[DonaldStott]

In an attempt to 'fix' the 100Hz hum mentioned in my earlier Posts I replaced the dual can capacitor (C2 and C3) with two 47uF 450V electrolytics. I also replaced C6 (16uF), C1 and C9 (47uF) along with C7 and C10 (25uF).

Unfortunately I now have an extremely loud hum and while the output from the mains transformer is 250V AC, the output from the rectifier is over 320V DC but gradually decreases as the hum increases? The current was measured at 60mA at this point and rising ... ! This is on the dim bulb to protect the other PCB components and of course I switched off immediately!

With the rectifier disconnected from the mains transformer and the PCB I measured the resistance from one of the AC input pins to the +ve DC pin and got 13.6MOhms one way and 6.2MOhms the other way. Similarly with the -ve DC pin I measured 7.6MOhms one way and 2.6MOhms the other way.

I think these readings point to a faulty rectifier although I do appreciate that the normal behaviour in such fault conditions is for the voltage to drop, not to rise to dangerous levels?

[Edward Huggins]

I just don't understand your voltage readings. The output from the rectifier is over 320V DC?

[John10b]

If I remember correctly that's about right, or am I mistaken?.
John

[Cobaltblue]

Has the EC1 bridge rectifier been "re-stuffed" with Silicon diodes?

Until the valves start to draw current there will be 320 to 340V on C3 since the capacitor will charge to the peak and no current is being drawn.

That the current is 60mA isn't too surprising although I am not sure where your measuring it, the anode current of each ECL82 is around 40mA per side + screen current, so total supply current HT1 is likely around 90mA

I have had a quick scan I didn't see if C3 and C8 had been changed although I did see a picture and they looked like hunts mouldseals if they are they need to be gone!

Cheers

Mike T

[DonaldStott]

Originally Posted by Edward Huggins

I just don't understand your voltage readings. The output from the rectifier is over 320V DC?

I don't understand the voltage readings either - I'm assuming that I’m clearly doing something wrong, measuring the wrong thing or in the wrong place? This is why I reached out to the Forum for help and support.

So lets go right back to basics - here is a photo of the Westinghouse EC1 rectifier showing the two orange wires coming from the mains transformer and the red and yellow wires going to the main PCB - where should I be measuring?

Originally Posted by Cobaltblue

Has the EC1 bridge rectifier been "re-stuffed" with Silicon diodes?

No evidence that the rectifier has been re-stuffed?

Originally Posted by Cobaltblue

I have had a quick scan I didn't see if C3 and C8 had been changed although I did see a picture and they looked like hunts mouldseals if they are they need to be gone!

C3 and C8 have been replaced with 470pF 1000V ceramics.


Before starting work the hum was at the usual background level typical of record players from this period and assumed that the filter capacitors needed replacing? This was done along with all the other electrolytics and some resistors but now the hum is much, much worse than it was! Previously it was around 35-40dBA whereas now it is 85dBA i.e. Industrial workspace (noisy machinery)!!

All the components in the power supply forward of the rectifier have been double-checked - R4 & R5 and C2, C3, C6.

I’m coming round to the notion that I have a grounding issue, although the lamp limiter doesn’t show a short?

[Station X]

I assume you have the service sheet?

This clearly shows the DC voltages you should see on the positive side of C2, C3 and C6.

Remember that theses are "on load voltages" so the valves will need to be inserted and warmed up so that they draw current.

The C3 measurement is the same as measuring on the red and yellow wires from the rectifier.

This assumes no one has screwed up the wiring or inserted electrolytic capacitors the wrong way round.