I never had problems with it before, and I don't use it that much. Then when using it today, when it was in my hand , the fan, and the LED display cut out. I had it on 400C, and only for 1-2 minutes, I was only removing 1 op-amp. Flicking the switch did nothing, so I thought it was the extension cord, plugged it back in, and it came back.
Then later, I was removing a few caps, barely had it on for 2x 2-3min sessions, and I placed it on the holder, and it cut out just like before, without cooling itself 1st. Then I couldn't get it to do anything since.
So I have it apart, the hot/neutral are wired right, the fuse, switch, and primary winding are good, and so's the 2x half-wave rec's for the 2x secondary windings. The PCB is pretty dirty looking on the main side with all the parts, and there's a few solder balls.
I was right in the middle of another repair, I want stuff to repair, but this is bad timing. Aside from the ATMEL 632 and S3F94C4EZZ-DK94, I should have all the parts to replace anything on the PCB, including the 600V triac.
Before I dig right into it later tonight, and hook the PCB to my bench PSU, or start pulling the silicon to check....does this sound familiar to anyone ?
I still read 120V on the mains, and now powered with 10V for the control, and 29V for the fan, the PCB alone lights up and seems ok. Now for more voltages checks.
IDK what 10A circuit the mains was on, I had a computer and a heater on, in the room with the 858d the 2nd time, the 1st time, it was in another room, on an opposite wall. The wiring here is modern, up to city standards, so don't think that was the cause.
The 5V reg is good, the TIP122 is for the fan I guess, and it's base is off, as is it's base driver BJT w/o the 10k fan pot connected/
I guess I better check the triac next, with the isolation trans., but I just want to get it back together
Ok I found the schematics, and the mother of assumptions was all wrong, no doubt there's a -5V rail. I never checked enough. Important lesson.
Then later, I was removing a few caps, barely had it on for 2x 2-3min sessions, and I placed it on the holder, and it cut out just like before, without cooling itself 1st. Then I couldn't get it to do anything since.
So I have it apart, the hot/neutral are wired right, the fuse, switch, and primary winding are good, and so's the 2x half-wave rec's for the 2x secondary windings. The PCB is pretty dirty looking on the main side with all the parts, and there's a few solder balls.
I was right in the middle of another repair, I want stuff to repair, but this is bad timing. Aside from the ATMEL 632 and S3F94C4EZZ-DK94, I should have all the parts to replace anything on the PCB, including the 600V triac.
Before I dig right into it later tonight, and hook the PCB to my bench PSU, or start pulling the silicon to check....does this sound familiar to anyone ?
I still read 120V on the mains, and now powered with 10V for the control, and 29V for the fan, the PCB alone lights up and seems ok. Now for more voltages checks.
IDK what 10A circuit the mains was on, I had a computer and a heater on, in the room with the 858d the 2nd time, the 1st time, it was in another room, on an opposite wall. The wiring here is modern, up to city standards, so don't think that was the cause.
The 5V reg is good, the TIP122 is for the fan I guess, and it's base is off, as is it's base driver BJT w/o the 10k fan pot connected/
I guess I better check the triac next, with the isolation trans., but I just want to get it back together
Ok I found the schematics, and the mother of assumptions was all wrong, no doubt there's a -5V rail. I never checked enough. Important lesson.
Last edited:
