9440A - relay clicks, no output
Had a burnt control board, replaced most everything on it. replaced E.caps on driver boards - just a few. Hooked it up to lightbulb C.L. and variac. Surprised me, lights came on around 50v, heard the relay click in around 60v. No smoke at 110 so plugged it into the wall, turned it on, in what seemed like the appropriate amount of time, heard a big click. Measured bias at outputs, spec is +-3mv, 1 channel was -2.7v, other channel was 6.6v. Tried adjusting 6.6, didn't move. Thought I ordered new potentiometers but didn't, thought could easily be why and 6.6mv was good enuff, wanted to hear one of these . no one around so did a victory dance - yea, fixed it.
Hooked up speakers and to a preamp using 1/4" jacks from cables I put together - basically pin to pin, other 2 wires to ground - turned it on, heard the click - no sound
Just in case, swapped preamps - no sound.
Used xlr to RCA adapters - no sound
Forget their number but the transformers are in it. Just in case, I swapped them with the other amp.
I'm going to go over schematic, start comparing voltages. Just thought I'd ask in case it was something someone was familiar with. I thought for sure when that relay clicked I was good to go.
Should not have done the dance until I heard sound :)
any info always sincerely appreciated
Re: 9440A - relay clicks, no output
Quote:
Originally Posted by
donberry
Had a burnt control board, replaced most everything on it. replaced E.caps on driver boards - just a few. Hooked it up to lightbulb C.L. and variac. Surprised me, lights came on around 50v, heard the relay click in around 60v. No smoke at 110 so plugged it into the wall, turned it on, in what seemed like the appropriate amount of time, heard a big click. Measured bias at outputs, spec is +-3mv, 1 channel was -2.7v, other channel was 6.6v. Tried adjusting 6.6, didn't move. Thought I ordered new potentiometers but didn't, thought could easily be why and 6.6mv was good enuff, wanted to hear one of these . no one around so did a victory dance - yea, fixed it.
Hooked up speakers and to a preamp using 1/4" jacks from cables I put together - basically pin to pin, other 2 wires to ground - turned it on, heard the click - no sound
Just in case, swapped preamps - no sound.
Used xlr to RCA adapters - no sound
Forget their number but the transformers are in it. Just in case, I swapped them with the other amp.
I'm going to go over schematic, start comparing voltages. Just thought I'd ask in case it was something someone was familiar with. I thought for sure when that relay clicked I was good to go.
Should not have done the dance until I heard sound :)
any info always sincerely appreciated
Check the serial number of your 9440. Serial numbers up to #1660 were missing lock washers under at least
some of the screws mounting the driver transistors. They often would loosen during shipment to the dealer,
and be dead on arrival. Service dept. replaced the transistors (tightening the screws), and everything was OK. Until the unit was shipped back to the owner. A local guy picked up a new one at the warehouse. DOA when he
got to his place. Immediately drove back to the factory and delivered it to engineering. Problem was identified
and solved! If the s/n is above 1660, I don't have any suggestions. Good luck with it.
Russ
Re: 9440A - relay clicks, no output
hate to show my ignorance this easily but serial #'s on the pcb boards ? U know, I don't see a serial # on the chassis unless it's some numbers on the side that look almost randomly placed there - well above 1660
Re: 9440A - relay clicks, no output
Quote:
Originally Posted by
donberry
hate to show my ignorance this easily but serial #'s on the pcb boards ? U know, I don't see a serial # on the chassis unless it's some numbers on the side that look almost randomly placed there - well above 1660
The s/n is on the outside upper right of the heat sink shroud on the back of the amp (It has openings for 2 fans). If the shroud is not there, you can simply remove the top chassis cover, and look at the driver boards on the left and right inside chassis panels. Each board has 2 metal-cased transistors (Q14 and Q15) screwed to the pc board. You can easily see the star washers under the heads of both mounting screws. Again, good luck.
