shardian
New member
Okay, this one is really perplexing me.
Display is out. I've seen it work a few times, but then fade back out. Checked the HV section - -100 large resistor was no good (open), +100 resistor was out of spec high. With displays unplugged, voltages are okay. With display plugged in, -100 goes way down. I rebuilt the HV section, and went over the displays with a fine tooth comb.
You see, someone (poorly) replaced the display glass once upon a time. I went through and checked for shorts, then continuity checked connection. I did find one cut trace that I jumpered.
Still, no dice. The last time I turned it on, I saw sparking on the 3 leg chip on the heat sink in the -100 circuit.
Now for the weird part:
1. The fuse never blows
2. Testing the HV circuit immediately after power down the 2W resistor tests open or higher resistance. If I wait a while, it tests okay. I assume it has something to do with the spark I saw on the heat sunk chip.
So...what is going on here? A shorted display should pop the fuse, right? I put brand new 1/8 fuses in, so I know they aren't over rated.
I think I'm gonna have to buy a new display. If anyone has a working sys11b display, I sure could use one! I'd rather not pay $200 for a pinLED display.
Display is out. I've seen it work a few times, but then fade back out. Checked the HV section - -100 large resistor was no good (open), +100 resistor was out of spec high. With displays unplugged, voltages are okay. With display plugged in, -100 goes way down. I rebuilt the HV section, and went over the displays with a fine tooth comb.
You see, someone (poorly) replaced the display glass once upon a time. I went through and checked for shorts, then continuity checked connection. I did find one cut trace that I jumpered.
Still, no dice. The last time I turned it on, I saw sparking on the 3 leg chip on the heat sink in the -100 circuit.
Now for the weird part:
1. The fuse never blows
2. Testing the HV circuit immediately after power down the 2W resistor tests open or higher resistance. If I wait a while, it tests okay. I assume it has something to do with the spark I saw on the heat sunk chip.
So...what is going on here? A shorted display should pop the fuse, right? I put brand new 1/8 fuses in, so I know they aren't over rated.
I think I'm gonna have to buy a new display. If anyone has a working sys11b display, I sure could use one! I'd rather not pay $200 for a pinLED display.

