Help repairing Altec 9440A amplifier

**scholzee** · August 7th, 2012, 06:41 AM

I am trying to help my brother repair his amplifier , it powers speakers by his pool. Its in an enclosed sun porch and he brings it in the house for winter. He hooked it up this summer and no sound quickly followed by smoke. We connected up a cheap amp and things sound ok so i do not believe it was a wiring or hook up issue. I attached a picture and control board 27-01-044590-6 has a burnt spot and output board 27-01-044591-6 is charred also. I am an elecronics technician by trade but do not typically work on vintage equipment. It looks like I may be better off trying to purchase used boards as the traces and parts of the output board are heavily damage. The control baord may be able to be salvaged. I am able to follow and interpt schematics and have all the test equipment to fix this, just looking for advise from more knowledgable people here who have experience with this gear. Thank you for all replies !!

**gvasale** · August 7th, 2012, 12:43 PM

May have been an insect that found a new home...Too bad.

**Old Guy** · August 7th, 2012, 05:31 PM

Try Iratech

Ira Tec Pro Audio's Homepage

**donaldpatten** · August 8th, 2012, 07:20 AM

You may have chlorine deposits on the PCBs. Scrub everything with soap and water and let it dry in the sun for a week. Test the output and driver transistors for shorts. Isolate the power supply from the rest of the unit and see if the power supply comes up. When a PCB burns and arcs over you need to replace the board or grind away the carbon trails. If you have a Variac bring the AC line up slow and monitor the current or power draw to keep from causing more damage.

Don

**scholzee** · August 9th, 2012, 06:13 AM

Thank you for the replies !! the room its in is away from the pool with widows that are never opened , none the less a good cleaning of the boards is needed , I belive this maybe the first time it was opened up. Don yes I have a Variac and thats a great idea to power it up like that. luckily he has a cheap amp working for now so I actually have till next spring to get it working again. That will give me time to identify on the schematics what burnt and hunt for replacements. Thanks agian and if there are anymore ideas I certianly appreciate it.

**donaldpatten** · August 13th, 2012, 09:21 AM

Did this amp take a lightning strike ?
Did the large cap on the right short ?
I am guessing the supply voltage is +/_ 50 VDC
Did you find a free schematic on line ?

Don