Jerome,
Do you have another scope that you can use to trace signals with?
Why is the fan no running now? Did you blow-out a power supply line?
If I get sometime today, I'll try to dig into the books and give you some more suggestions.
I have 2 working 468's that I've repaired. Both had problems in the digital storage section. In one, it was bad EPROMs. In the other, it was the microprocessor's TTL clock oscillator. The 468 scope is neat scope. I use mine ocassionally to troubleshoot things like switching power supplies and other oscillator circuits running under about 5 MHz.
Jimmy
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--- In TekScopes@..., "jeromequelin" <jerome.quelin@...> wrote:
So here's a new episode in my troubleshooting adventures. While following one of the diagrams (troubleshooting diagram number 3, the non-storage portion), I encountered a note recommending that I disable the storage section of the scope. It took me a while but I eventually found directions on how to do this. But these are kind of crude and I am not sure I did everything correctly:
1. Disconnect P3008 from the A12 Trigger Generator Sweep Logic board (see Figure 8-17)
2. Disconnect P483 from the A23 circuit board and connect a jumper between the two square-pin connectors on the board. I found this to be a bit confusing: is it asking to short the two pins of conector P483 with a jumper (which I did by soldering a piece of wire) or should I short more than one connector, and if so which one?
3. Move P307 (at the rear of A14 Vertical Mode Switch board) to the Test Mode position (see figure 8-15). But what is this Test Mode position? I am sure it is referenced somewhere in the 600 pages but after a couple hours of skimming through both volumes I can't seem to find it. There's no mention of a test mode connector on A14's schematic. The only thing I could see is this other connector, P206, that is sitting on top of P307. I switched 307 with 206 it but the scope wouldn't display anything and the fan was not turning anymore.
So I must have gone wrong somewhere and If anyone knows how to disable the storage unit, any guidance would be greatly appreciated. Thanks for your patience with my lack of experience, I'm really enjoying this repair so far!
Jerome.
