Yamaha T-33 schematic- ABANDONED

[CT Jim]

Simple inexpensive tuner, but does not power up. Another Aker has one of these and uses it without the display, but this one won't even power up?
I'd like to give it an hour before scrapping it!! Cannot find a SM or schematic, I think a model T-10 has the T-33 within it's manual?

 

[CT Jim]

No one has a schematic? not worth putting a pot of money in it, but the challenge is always lurking in the background!!

 

[rcs16]

Did you check hifiengine? I did no lucky. Show a pic what is in it, if you scrap it, might be some parts to keep.

 

[CT Jim]

I do check around, hifi engine and other places, but I don't want to buy a SM for $15 when if working I might get $20

 

[chazix]

the challenge is always lurking in the background

Well, heck, how much challenge would there be if you had the service manual?

It's a virtual certainty that there will be one or more heat-sink-mounted semiconductors that serve as voltage regulators, so you might start by locating those, figuring out which pins are input and output, and seeing what voltages are on those pins.

In what's probably the most likely example, the heat-sunk part will be a transistor, with its collector as the input and its emitter as the output.

I'd best not try to elaborate much more without knowing whether I'm already way off base...

Cheers,

chazix

 

[rcs16]

A picture of the innards would certainly help. Could try/check the AC line fuse to start with

 

[CT Jim]

Thank You for the obvious fuse suggestion....
Having the service manual would provide a few places to check readings to narrow down where it doesn't get thru. I have no desire to spend hours screwin around with a $15 tuner, it's worth an hour to me, after that off to scrap and I'll continue with my regular power and speaker projects. I do hate to junk stuff, but parting it out doesn't seem very practical.
Maybe I'll just put it in BT for parts, and move on.