I tried that it didnt work. so i returned it. I sent the link to the lowes one in the post above. I think one of these should be ok. It states that it does 400.0m ac voltage. its only 15 bucks or so more than the radio shack one.
heres a link to the site from the company.:

http://www.idealindustries.com/products/test_measurement/multimeters/test-pro_340_series.jsp.


or this one.
http://www.extech.com/instruments/product.asp?catid=48&prodid=277

ill pick one up in the am and retest all of those voltages and repost.

it has a 4 volt ac setting, I bought the one you posted from radio shack. ill return it and get a different one from lowes. I get no reading from playing a guitar chord. ill retest the u18 u19 ic in the am after work and getting a better multimeter.

ill try this multimeter

http://www.lowes.com/pd_136122-12704-61-340_0__?productId=3127727&Ntt=mulitmeter&Ns=p_product_price|1

Ok I got a new multimeter. here are my results....

yes i still hear the same with the 44100hz signal into j9.
u18 pin 5 yeilds 7.5v dc
u19 pin 5 yeilds 7.09v dc
u18 pin 6 14.9v dc
u19 pin 6 19.95v dc

here is the ac part im not sure about. when i set the meter to measure less than 4v ac i get 0.05 on pin 6 on both u18 and u19,

but i read in the manual for my multimeter that to measure ac voltage on a dc source bias i need to connect a 0.1 microfarad mylar cap at the end of the positive test lead. isnt that what im measuring on this circuit? Do i need to go buy a cap to test the ac voltage correctly?

P.S. thanx for all the help.

OK JM,
the out to the headphones actually needed to be powered. i sent out to my pa good both sides. in from a cd player the same side is distored and weak. j9 is both the stereo input and the stereo output on this model.

Sorry Roly, got excited when i saw the burned resistor. I did read the posts.

Here are the schematics.

As for the effects loop.... I jumpered it and the weak channel sounds the same, no distortion. it is not a stereo effects loop. the send /recieve jacks are the same part as the 1/4inch input jack. they are not trs.

(Side note I replaced the resistor to no avail)

After googleing around I found the service manual... long story short it has a pic of the PCB and a part list. hopefully this is the bad part and i'll be set after replacing it. I'll update after I get it soldered in.

I think I found the culprit. After testing the amps internal speakers I found that only one was working so I opened it up and  followed the path from the speaker contacts and found this burnt resistor/inductor. not sure which it is.

the green one in the center of photo one with the red/gold/black/brown bands.

Can anyone help me ID this so I can go to radio shack and order one?

one more thing. there are two internal 6.5inch speakers that I just assume have equal output but it is hard to tell just by listening. I guess i could hook a multimeter up to the wires going to each internal speaker and check that the output is the same also. correct?

Roly,
Yes the is a stereo model, but according to the user manual the effects loop uses standard guitar cables so trs stereo cables are not required if I am using the effects loop. So if i understand you correctly i should connect a cable from send to return and see if the weak side is distorted or not? there are no left and right returns. there is however an aux in/stereo out 1/4 inch jack on the back also. i guess i should check to see if the signal is the same comming out of that to my pa or something huh?

kinda a newbie, but i have built a few effects from kits and such.

I just aquired an old Gallien Krueger ML250 from my dad. the input jack was broken and I replaced it with no problems. The issue Im having is the output jack on one side is maybe half the volume of the other side. the circuit board look ok with no burns at any of the componet sites. it will drive a 2x12 on one side well. I have a multimeter, a good soldering iron, and some knowledge. where do I start? Pix will follow if anyone can help.

Thanx all