Idol pro IP 888

[catstrat]

This may be an odd request, i have an Idol Pro IP 888 karioke mixer/power amp on my bench. Does anyone on here know anything about these ? I contacted Idol and they don't give out schematics. I hope someone has the schematic. Thanks.

[Enzo]

What is wrong with it?

[catstrat]

Hi Enzo

To be honest Enzo, i guess i need to make sure that i know how to hook the thing up. If i'm hooking everything up right, the music input which i believe is on the back of the unit at the RCA plugs, the left channel is low volume. The right side is fine. The mic inputs are fine. I fixed that already. I'm still trying to get my head around this thing. Let me verify a few things and if i still need your help i'll let you know. Thanks Enzo.

[catstrat]

The last Idol pro i worked on is working now. Now i have number two on the bench. It to is an Idol pro IP 888 just like the first one. This one the relay is not engaging. I removed the main board and found a burned 2.2k 1/4 watt resistor burned to a frizzel. I replaced it and also a couple of electrolytic caps. I tested the relay and it works fine. Anything i should check before i put it back together? Thanks

[catstrat]

I think i got it solved. I plugged it in to my variac, wonderful little device, and brought up the power to about 20 volts ac and i was pulling about 3 amps. Not good. I left it on and feeling of the O/P transistors,2 were getting really hot. Removed board and removed both transistors, connected everything and brought up power to full ac voltage and no excessive amperage draw. Did find a bad driver also. It was causing a 100 ohm resistor to overheat. Removed it and that cured the overheating resistor. I'm hoping all those parts are shorted. But i'm not ready to call it fixed until i get the parts installed. What else should i check after i install the new parts and test it? I think the emitter resistors should be tested. If i'm overlooking anything let, let me know.Thanks everybody.

[Jazz P Bass]

I don't have a clue what you are into there but you cannot check enough parts to guarantee that it will work.
Check the main items, do a few spot checks looking for stupid readings & go for it.
It sounds like you have the use of the variac & the current meter down pat.

[catstrat]

Idol pro

Hi Jazz P., Hope you're doing well. This piece is a karaoke mixer/power amp in one. It's made by a company called Idol Pro and of course, they don't give out schematics or anything else for that matter. I work mostly on tube guitar amps,pedals and stuff like that. I've always been afraid of power amps/mixers but i'm also passing up a lot of money. I've decided to jump in with both feet. You're right that removing the suspected bad parts stopped the excessive amperage draw but i don't know what's going to happen when i install the replacement parts. This is why i find solid state stuff so tricky. I've been successful in fixing other power amps using this variac method but i just don't trust my transistor troubleshooting skills yet. Well Jazz P, one thing is certain, it's either going to work or it's not. Just in case i'll call the fire department and have them on standby.

[catstrat]

idol pro

I installed the 2-2SC 5200 and a 2073 transistor and tested the amp and it's still pulling way too many amps. I removed the board again and starting looking at what i think are the drivers because they're mounted on the heatsink right next to the 2SC 5200. I decided to pull it from the circuit and noticed all 3 legs of it are broken by what looks like a prior installation, but i don't know for sure. So i need to order a replacement but, i can't find one. The number on this is"H669A". I checked Alldatasheet and they had no info on it. MCM didn't either. I hope it's not an in-house number. I'm not up on my transistor packaging but it looks like a smaller version of TO 220 . I'll try Mouser next but does anyone have any ideas how to remedy this problem? Is there a generic replacement for this? Since the people who built the thing don't give out schematics i'm flying by the seat of my pants. Thanks.

[Jazz P Bass]

It's possible that it is a 2SD669A.
2SD669AC pdf, 2SD669AC description, 2SD669AC datasheets, 2SD669AC view ::: ALLDATASHEET :::

[catstrat]

You are correct . The one thing they did do is they mark the board so i looked at the board and it said D669a so i assumed 2SD 669. I looked that up in my transistor cross reference book and it crossed to an "NTE 373" which i happen to have in stock. I made sure the pin out is the same because i ran into an NTE 85 that had a different pin out than the one it was replacing. I rely on guys like you because i'm still gun shy on transistor stuff and noone on here has steered me wrong yet.Thanks everyone. I'll let you know if this fixes it.

[catstrat]

I got the excessive amp draw problem solved and now i have no signal to the output. I did have a 7805 regulator getting hot so i replaced it but it might be a shorted transistor causing it. I checked the voltage at several of the op amps in the preamp and i have voltage where i'm supposed to have it. It would be nice if someone had a schematic on this. So i'm taking a break from this for now. Thanks