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Old 30th March 2004, 01:01 AM   #1
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Join Date: Mar 2004
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Question Problem with Randall Amp

Hello-pretty new to this forum, its my first post. Have been trying to get on here for a while now. Never got the confirmation email for ever. Everyone on this forum knows what they are talking about, its amazing.

I recently bought an older randal century 170 150w ss head off of ebay. Picked it up cheap just to have at college. The problem i am having is when i bought the amp, the distortion channel didn't work, the clean did... As i played it the clean channel got extremely fuzzy. This happened over a period of maybe 2-3 months. One thing i noticed is that once i turned up all volulme and gain pots for the distortion channel, i could barely hear it over the guitar. Not worth much , but it was trying. I have also noticed the volume does not get any louder on the clean channel after hitting 5 of 10 on the pot. I dont think it should be maxed out there, could be wrong.

One of my profs at school checked out the darlington transistors. (MJ15003) they both checked out fine. I pulled both boards off and looked around for broken/cracked/bad solder joints. Im almost positive its on of the op amps. they are (RC4558P), (JRC4558D), and (TL604CP) which i believe is a voltage reg.

Here is the schematic:

http://us.f2.yahoofs.com/bc/4068cfd1...uRNaABDH0_XLtA

Extremely terrible pic of pre-amp:

http://us.f2.yahoofs.com/bc/4068cfd1...uRNaABkmsz3BBI

Terrible pic of power amp:

http://us.f2.yahoofs.com/bc/4068cfd1...uRNaABOnyOdURw
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Old 30th March 2004, 04:31 PM   #2
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Correction to the above links

Schematic:

http://us.f2.yahoofs.com/bc/4068cfd1...kGbaABKt0mXLtA

Pre-amp:

http://us.f2.yahoofs.com/bc/4068cfd1...UNbaABzXRK3BBI

Amp:

http://us.f2.yahoofs.com/bc/4068cfd1...UNbaAB.SzVdURw
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