Rock-ola 490-1 Power supply / control unit Problems

[inspjoe]

I've been battling issues with the power supply unit and now unsure if the problem may rest with the control unit.
The Power unit LEDs are lit which I understand doesn't mean all is ok, on the bench (not installed the box) output voltages are are okay except for one (26VDC). I'm not sure if readings on the bench are valid with the box not installed. 

I'm starting to think the problem may be in the control unit, only LED lit is the system pricing (far left).

I've checked and or replaced fuses, caps, and diodes on Power supply and rectifier board. 

No scan, no lights (except for the fluorescents) tends to drive me back to the power supply.  

Any ideas would be appreciated


Joe 

[Ron Rich]

Hi Joe,
What's with the 26 volts ? ALL supply voltages must be correct ! What are you calling the "control unit"-- the computer ? If so, look st the connectors on it-- they often fail, as does the large ribbon cable to the door. Have you rep;aced the battery in the computer (didja read the sticky) ? Ron Rich

[inspjoe]

Thanks Ron,

I'll check the connectors, but my power supply output of 26VDC is not there, I've changed most of the diodes,  A06 transistor as well as the caps, the only item left in line is the LM317 regulator which I think is good.  

This is squeezing my brain

Joe

[jukenorman]

Do you have 45V on pin 2 of the LM317 regulator?
Norman.

[inspjoe]

Hi Norman,

Yes I have 45V on pin 2 of LM317, output 2.2, however; if I isolate Pin 2 (rectifier board connector), my output jumps to 45. Since I have already replaced the diode CR2 I'm now suspecting K1 relay as the NC contact doesn't appear to open when powered. Has anyone seen these relays as being problematic?



Thanks 


Joe  

[Ron Rich]

Hi Joe,
What "kinda" relay is this ? If an "ice cube"-plug in able relay yes-- as with all relays, contacts can be "adjusted to fail"-- Is this phono "new to you" ? Do you know if that plug in relay is the correct type for this app ? Ron Rich

[inspjoe]

Hi Ron,

It's not a plug in, it's a soldered PC board mounted 5 pin relay (R50-E2-Y1-24VDC), and is the correct relay for this Rectifier board. I suspect it because it has a normally closed contact to ground which opens (eliminating a path to ground) when the unit is powered. That path may be bleeding down my 26 VDC source. If it is that relay I'm in trouble as it's no longer manufactured and have been unsuccessful in sourcing a replacement.


Thanks


Joe

[Ron Rich]

Hi Joe,
OK--I'm lost-- is that relay being powered ? Is that relay contact not moving ? Ron Rich

[inspjoe]

Ron,

Relay coil is powered; however, it appears the normally closed contacts are fused and do not open as print indicates.

[jukenorman]

Hi Joe,
I have had a closer look at the schematic - it seems you have a 26VDC rail and a switched 26VDC rail. It looks like that relay is the play control relay and my understanding is that the relay needs to be de-energised for the switched 26VDC to be present ie the NC contact of the relay enables the adjust function on the regulator. Do you have 26VDC at pin 2 on the board (that's pin 2 with WHT-RED connected to it)?

Norman.

[Ron Rich]

Hi Joe,
If the contacts are "fused"-- clean emup/replace them Are you checking them with a meter --and if so, which kind ? -- SEE, the sticky in the FAQ's section. Ron Rich

[inspjoe]

Hi guys,

Norman I think that relay is my culprit as I removed it and used jumpers to simulate it energized, my voltage at pin 2 went from 2VDC - 25VDC.

Ron, it's a sealed relay and possibly solid state so replacement is my only option, the problem is it's no longer manufactured and can't find it so I'll have to get creative and adapt another relay type.

So I installed (with jumpers installed) it in the Juke box and now the record carrier rotates but the CPU / S2 doesn't light up except for unit pricing light. Now I think I'm into the CPU and my first order it to replace some shady looking caps and clean connectors.


Thanks guys