how to : Revising an amplifier?

[kevwilde]

Hi,

I've got the main mechanics working and now I'm investigating a sound issue: only one of the two audio channels is working.

I've got a couple of questions and some solutions I would like to check with you:

1. I need a way to run the amp out of the jukebox in order to test/fix it.

I'm thinking of using an mp3 player, transform its Line out to Phono
I also need to have an external 120V Power source, since I'm from Europe, we have 230V here, so I was thinking on using a transformer 230V to 2x115V. How much Watts does this transformer need to handle? (if it matters, the jukebox is a rock ola 436 centura)

2. I will probably need to test the transistors

Can I test these in circuit or do I need to remove them?

3. I will probably need to replace the capacitors

I can find cap kits on US stores, but shipping is costly and I would love to learn how to recap them, instead of just executing. How do you identify the caps that need to be replaced? Do you replace all caps or do you identify specific caps based on their purpose or their electrical characteristics? Is there any guide to identify this?

Kind regards,

Kevin

[Ron Rich]

Hi Kevin,
1. You need to be able to read the schematic, to tell if this unit will operate on a 230 source. I don't think an MP has enough out put (?). Yes-- the type of jukebox maters--as does the amp designating numbers !
2. Depends on how / what you use to "test" them ! Also the type of transistor, and the circuit it's in.
3. "Cap kits" usually replace only the electrolytic, and "paper" type caps. Check with the kit supplier-- as it says in our Off-topic/scams post-- know what you are paying money for, before you buy !
HTH-- can't give a 4 year electronics course here -- Ron Rich