Akai CR-80D-SS Help me ID the device not on the schematic

[cometphoton]

First of all let me explain my approach. I am a novice at making repairs, my electrical background is PLC controls so I understand what the parts are in the schematic. I can try to trouble shoot the circuits but I choose to replace all the parts when I identify a fault. I guess we could remove the parts and test them. But I will need help to how we test them too.

I need help to identify parts that exist on the actual PCB and not on the Schematics I found in the service manuals. Are they Diodes? If so Zener or what type? What is a suitable replacement too? In this image my tweezers are on a device I can't id. I never see a part like this. its blue and black?

IMG-8944

• cometphoton
• May 9, 2020

OSCIllator Actual PCB 1

IMG-8944

• cometphoton
• May 9, 2020

OSCIllator Actual PCB 1

The PCB in question is found in the AKAI CR-80D-SS Service Manual "ED-B505". The images I attached will help explain my story. Any comments will be appreciated. What I really need is part numbers to replace what I can't Id. Thanks again.

IMG-8940

• cometphoton
• May 9, 2020

Front view of the board

IMG-8940

• cometphoton
• May 9, 2020

Front view of the board

IMG-8942

• cometphoton
• May 9, 2020

Bottom view of ED-B505

IMG-8942

• cometphoton
• May 9, 2020

Bottom view of ED-B505

IMG-8941

• cometphoton
• May 9, 2020

Side view of ED-B505

The problem with the deck is:
1. Plugin unit and the solenoid PL-1 sticks on. ( solenoid gets hot as its only a momentary device ). I think PCB in question is the cause.

 

[cometphoton]

looks like a diode. 1n4003 etc should be ok

is it a 1N60 Vintage Germanium Diode ?

 

[Tenacea54]

If PL1 is engaging and holding in on powerup, the main culprit is the power transistor TR403. (the one heat-sinked to the metal tab). The collector (case) of this transistor needs to be completely isolated from the metal heat sink it's bolted to (which is grounded). If the mica insulator has a hole or the small plastic bushing that insulates the small metal bolt & nut from the transistor is missing or is damaged, the transistor will close PL1 and the track changer solenoid will remain "on"

 

[Tenacea54]

The diode you're looking at is D401. It is not a zener diode (zener diodes have a different schematic symbol than regular diodes) Zener diodes are usually found near the power supply circuits, as they are used to regulate voltage lines. BTW the service manual diagram of board D505 is way out of date, and of little use in locating components on the board you have. Several revisions must have occurred and the manual was never updated.

 

[Tim-in-nj]

What I can tell from having spent the afternoon is that the ED-B505 board in the manual matched the ed3 (edition 3?) board, where as the one you have is an ed4 (edition 4?) board, which has many more parts on it. I've one of each in front of me, and the ed4 is the one with the issue.Anyone got a revised schematic?