I have a 4040dsm amp with a blown channel. 1, 2, and 4you work but 3 is dead as a doornail. Opened it up and no visually bad components. Any ideas on how to start testing it? I suspect its part of the output section that's bad, but this is the first electronics I've tried to repair without something obvious being bad. Thanks and ill post ia pic later
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Anyone run memory speed tests with an old X58-based triple channel 1st gen or any other >2 channel board? The one I have is a Gigabyte I think.
Anyway I had four 4GB DDR3-1333 modules in the 6 memory slots and got around 11GB/sec memory speeds assuming that it went dual channel since it didn't have enough modules for triple channel. Now I stuck in two more 4GB modules, but they are DDR3-1600. I'm still getting 11GB/sec speeds according to memtest86...
Just wondering, anyone do memory speed analysis on these triple (and higher) channel memory boards? Are there any... -
Hi friends
I have reverse engineered this tester, schematic is attached and is complete except for capacitor values. These testers annoyingly have no model number but they are the ones you find on the first page of just about any website if you type in "18650 4-channel tester". There is also a 2-channel variant and a newer 8-channel variant. They are very cheap (about £15) and can measure voltage, current, internal resistance and capacity. They have a multicolour display for all these statistics. They also have terminal blocks so that if you want to use a breakout board... -
Hello,
I'm repairing a Denon AVR-X2000 that has blown both FR channel output stage transistors. Upon replacing the transistors (Q416 and Q422) witch a matched pair and replacing both burnt 22Ohm base resistors (R458 and R483) the unit powers up and I was able to set idle current to spec (8mV on test points) across all channels except for the FR channel that had a problem, it tests 0V and I'm unable to adjust that at all. The transistor (Q421) which regulates the bias current tested okay (it sits between the big transistor pair). Also I'm unable to produce any audio from any channel.... -
Hi all forum members,
Fyi, i have been working on this old model PCT-4082 (4 channel car amplifier). The owner said only one channel is working.
My initial finding is this amp originally use Toshiba 2SA1943 and 2SC5200 transistor for its output but after opening the top casing i found it used Toshiba A1941 (pnp)and C5198(npn). I desoldered all the 4 pairs transistors and found 1 piece A1941 open(tested "OL" on all legs) and replaced the 1st pair with 2SA1943 and 2SC5200, thats why you can see in the picture it is the bigger size transistor. The other A1941 and C5198 all... -
Hi guys I have a VLP1500 amplifier here - one channels works fine and the other channel distorts even at low volume settings
Protection and Clip LED are off
There is something wrong with the BIAS voltages around T16 and T18 (in particular) on the bad channel
I tested all diodes and transistors in this area in circuit with diode mode - both channels seem identical. Same in resistance mode across all the resistors here.
The output DC voltages on pin1 and pin8 of the 5532D dual op amp at the input of each amplifier module are the same, and the audio...