Recent content by robertgalka

It looks like JBL had two different motors, or magnets on these also. The binding posts on most of these are at 3 o'clock and 9 o'clock. On my 2404H1s they were at 2 and 8 o'clock. I sold everything so I can't take pictures, but doing an image search I've found pictures of both types. You can...

I know I used the magnet and diaphragm on a 2404 on a 076 a few years ago. It was easier than changing the diaphragms. There also is two versions of a 2404, one is called a 2404H1. I know they are not interchangeable. They used at least three different nose pieces also. I would just find a...

I turned it on and let it sit for about 30 minutes. I checked the bias voltage and both sides were between 24 and 25 mV. I played it a bit and both sides were very close to the same temperature also. The cover is back on it and hopefully it never has to come off again. It also seems like I can...

So the side that was running at a normal temperature all of a sudden decided it wanted to get really hot a few days ago. I pulled it apart and changed every Thermaltrak transistor. The side that was originally running hot had four original transistors, so I changed them also. Everything seems...

I changed that one transistor that was getting hot, and everything is good now. I’m still going to monitor the temperature of the heat sinks for a while. Thanks for the help.

I turned mine on for about 30 minutes without a signal going to it, and it was around 90 degrees also. I see mid to high 90s when it is played at moderate levels.

I bet whoever repairs it will change all of the transistors. I changed 8 out of my 12 and the problem is almost solved. I just have one that is hotter than the others. I am waiting for an order of 25 NJL3281NDs so I can change the rest. They were zig zagging across the continent, now they are...

Do you know the date on your transistors. Mine are 0731. I’m assuming that is the 31st week of 2007.

I would still monitor the bias for a few days. It was all over the place on my MA7000. Does your manual say 25mV also?

If you email McIntosh directly, they will email you a PDF version of the service manual. You will probably need your serial number in case they did a change up. The transistors that were bad on mine are in stock at McIntosh, they are $12.00 each. The NJL3281DG seem to be out of stock everywhere...

We had a rainy day so I took the board out changed the remaining four remaining NJL1302DG transistors. I only had two NJL3281NDs for the other side of the same board, so I changed them also. I have 25 coming, but they are somewhere between here and LA. It seems like one of the new 3281s is...

I should also try swapping the boards from right to left and see if the problem changes sides.

I ended up changing two of the transistors yesterday that had the highest voltage. It seems to behave a little bit better, but the bias voltage spiked again and it got hot. I think it took a little more volume to get it up to that point now with the two new transistors. I turned it on today...

So it seems there are two transistors where the voltage is higher than the rest. When the bias voltage starts to rise, they are at least 10 mV higher than the rest of the others on that side. They were also slightly hotter than the rest when I used my laser thermometer. I may attempt to change...

By looking at the schematic, it looks like the centre pins of R14-R19 are connected directly to J4. Also pin 1 and pin 3 are connected directly to pin 2 of the transistor? We might have reached the point where I am a little to ham fisted to continue. I might have to remove the heat sink and...