Yamaha p2200 blowing fuses

[Pigpen1972]

Hi guys,

I'm brand new here...this is my 1st post. Your help would be much appreciated. I've searched many forums for a clue to my problem, and I've come to the conclusion that you guys are the most knowledgeable on this matter...

...I've got a Yamaha P2200 that I've had for 14 years (I used to have 2). They were absolute workhorses that I NEVER had any problems with. I ran them hard 4-7 nights a week for 4 years in a demanding environment as a club DJ. These are classic amps from 1976 that spent their previous life in a theater in Branson Missouri.

Since 'retiring' from that biz 9 years ago, this amp has had limited use, and has only been use a couple times per year. The other day I plugged the amp in, and turned it on. It powered up, then immediately shut off. I checked the main fuses (Which had NEVER blow before), and they were both blown. I replaced the fuses with new ones of the proper size, turned it on, and the same result...It powered up and immediately died.

I'm not electronically inclined with regard to circuit boards, so I'm puzzled...any ideas? If you guys would please help me out, I'd appreciate it. I'm not a DJ anymore. I'm 38 now and starting a new band, so I need the amp for PA, but am on a rather tight budget right now.

Thank you guys - Paul

[aparatusonitus]

Hi Paul,

Welcome to the forum...

First, download service manual for your amp here YAMAHA P 2200 SM Service Manual free download, schematics, eeprom, repair info for electronics you are in need for one. I'm not smart enough to lead you through process of finding offending component(s), but someone around here definitely are.

[Pigpen1972]

This is a great start...thank you.

[nigelwright7557]

Its usually something pretty fundamental when the fuses blow.
I would isolate the power amplifier and check the power supply first on its own.
If the power supply is OK then it is possible it is the output transistors.
Check them for short circuits.

[Enzo]

Everything works until it doesn't.

When amps blow fuses, first thing on the list is shorted output transistors. Check. Next would be main power supply rectifiers. Other things like shorted filter caps are less likely.

One thing I'd suggest is to look closely at the circuit board for the power amps. You might see some single transistors on individual little heat sinks - as opposed to the row of transistors along the main heat sink. Sometimes those individual ones crack their solder.

And aside from shorted parts and cracked solder, sometimes a missing power supply voltage can cause trouble.

[sakis]

P2something series are as you describe them workhorses but having a reputation of blowing spoeakers if pushed very hard ...

first thing to look at is as said above is the power supply better seperated from the amplifier ....a blown rectifier ...clamp diodes ...and blown outpouts is places to look at ...

outputs are very common to blow but also common to find in matched pairs in YAMAHA service centers ... prize is bit jiiiizzy but the semis are trully original

post pictures of your problems and progrees and you will get all available help

happy regards sakis

[Ozelator]

if all the info these guys gave you dont work, mail me, i will give you a detailed description on fault finding...

BTW thats a pretty sweet yamaha. im use to working on the newer one's with the switch mode power supply.