I am having trouble with my quad Channel 1 lead "completely dead".. Mine its a 1986 model and look like never been service after almost 26 years.. So i was thinking about take it to a local tech and doing a complete overhaul service to the preamp.. So need some good advise on what parts should i get and what should i do. Probably i would need to get all the parts myself so if you are all kind to tell me some place on line to get it, i would be very grateful. I live on Puerto Rico so parts aren't available on my area!!!
Trouble with my Quad Preamp lead channel 1 neede advice!
- Thread starter mxr2000
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maybe is something like that but the true is that my preamp is from 1986 and sooner or later something else will fail for lack of maintenance (re cap,ld's change,etc,etc).. Can you help or somebody else find an ON-line place to get all the parts that i need besides Mesa Boogie ?crane said:
crane
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You want to change everything in the Quad ? That will cost you some money !
LDR will fail one day or another, so you can change them (150-200$), power filter cap too (20$).
But I would personally not change anything else without a failure. Resistors can last forever, audio cap last very long too, especially because Mesa used to build stuff with component with a great derating (every component is "oversized" for its use, for example audio cap that support 600V although there is no more than 300V).
LDR will fail one day or another, so you can change them (150-200$), power filter cap too (20$).
But I would personally not change anything else without a failure. Resistors can last forever, audio cap last very long too, especially because Mesa used to build stuff with component with a great derating (every component is "oversized" for its use, for example audio cap that support 600V although there is no more than 300V).
daveyboogie
Well-known member
+1 plate resistor.
Check for correct resistance/continuity from 450V rail (big cap) into pin 1 and pin 6 of V23 socket thru the 82k and 270k resisitors respectively. I bet one of them is open circuit. Snap the culprit in half with needle nose pliers then solder a new resistor onto the legs of the old one. 10 minute fix if you're good with an iron. Just promise you'll unplug from mains first!
I ran mine like that for nearly a year before LDR issues forced me to do a proper job. Don't worry about reliabilty and don't attempt to change everything, re. Crane: He speaks the truth.
http://tubefreak.com/s-lead.gif
Check for correct resistance/continuity from 450V rail (big cap) into pin 1 and pin 6 of V23 socket thru the 82k and 270k resisitors respectively. I bet one of them is open circuit. Snap the culprit in half with needle nose pliers then solder a new resistor onto the legs of the old one. 10 minute fix if you're good with an iron. Just promise you'll unplug from mains first!
I ran mine like that for nearly a year before LDR issues forced me to do a proper job. Don't worry about reliabilty and don't attempt to change everything, re. Crane: He speaks the truth.
http://tubefreak.com/s-lead.gif
