Hi- I had triggering problems with all modes. They all use the same trigger chip. As for photos, I don't have any, but if I dissemble the unit again in the coming days, I will take some for you.

well, at least inexpensive progress was made.

Thanks for your replies. Yes, I replaced every electrolytic cap in the oscilloscope and cleaned the Boards with aerosol. Just took out the front panel board again and cleaned it with water, dried

That's not how digital processors work. The two aspects are completely separate. There's no conflict in that. I put away the TDS694C for the night. It's 02:45h, my bed time... Raymond

Ray: I really don't know how they share those functions across the trigger chips. But this whole thing is starting to smell like a firmware bug that 'triggered' a hardware hunt. If the trigger or acq

Agreed, and that's my plan; sorry I wasn't more explicit. Although it is difficult to be certain since they are horizontally spaced, I currently believe the three dots are there whatever the sweep

I would not borrow trouble; it is probably ripple on output of the low voltage power supply and even if it is something else, the ripple needs to be taken care of first which means changing the

I don't think there's anything wrong with doing that. The delay tubes are still available but are getting scarce. I had a problem with a few of them burning out quickly in my 555, possibly due to the

Thank you. Got the colors reset. Kinda weird, for me, is that in default mode the grid is not showing.

Hello Group, Thanks for all the info. At this point I want to order A4CR4122 and A4CR4123 DC restorer diodes. These are P/N FDH5004 but are no longer available. Can someone confirm that a 1N4936 will

Correct! And so does Delayed Only! Now please tell me the division of the trigger functions across the trigger chips... Raymond

Ray: Try this: Go into the Horizontal menu, switch from the Main time base to Intensified while in Ch3 or 4. Suddenly the issue goes away! CH3/4 works in edge mode!

Thanks, that makes sense, and is what I was hoping. The mains cable isn't new (it even has string/hessian inside it), but is the familiar brown-blue-green/yellow. The Tek logo is still there, and

It was a good idea to use a TDR.  I don't have a dedicated one but I could just use a signal generator and a scope to time the reflections.  It would probably be accurate enough.  I just got lucky

Will do but I've got plans for other things first and I want to be careful for this, so it may be a while. A small complication is that I stuck VGA-card RAM-chip cooling fins on trigger chips #1 and

Well, Ray, be sure to take some pics while u do that. I can't open my unit yet as i have a 30 day right of return, unless I break the cal stickers. Axiom is insisting they did a proper cal and all was

David, AFAI've checked, yes, it does. I take variable persistence as the setting for DPO functionality in this 'scope; it gives a colour-coded density graph ("heat" or "spectrum" and the like). The

Tek produced a considerable number of 475 scopes, and somewhat fewer numbers of previous models, for IBM to use for on-site service applications. In the case of the 475, the purchase contract asked

Does the DPO functionality work with logical and pulse triggering? The chips under discussion may only implement the edge triggering needed for equivalent time sampling or jitter reduction.

Just to clarify James. You could NOT edge trigger on Ch3/4 until u reflowed the Trigger chip? But you could get Pulse & width triggering to work before the fix? BTW having not dissasembled this scope