Yeah, the HV supply works around 45kHz on this one, but this problem is definitely happening at line frequency. If I line sync the sweep the intensity banding is stationary.

Thanks Harvey - I think my next step is to change out those few HV caps in the neighborhood. They're all pretty low value disc caps, which tend not to be components I suspect when looking for 60Hz rip

Hi Folks - I'm seeing an intermittent intensity modulation at line frequency on my 564, and have been unable to measure the source. I've tried both a 3B3 timebase, and a 3A72 in the horizontal slot wi

I think the best compromise might be the 3 pole midget twistlock from Hubbell, as it will give me a grounded connection, and the modification will be the lest conspicuous: slightly enlarging round hol

Thanks Bruce - 'General Electric' extension cords is giving some good hits. I guess these weren't grounded via their AC socket?

Thanks! An IEC socket /almost/ fits, but would require a little bit of filing, and maybe a plate to fill in the remaining gaps. I'll take a look at the EP - I think I remember seeing them on consoles

Does anyone know of a source for the cable-end receptacle that mates with the plug shown in this photo https://w140.com/tekwiki/wiki/514#/media/File:Tek514-lineSocket.jpg The inside is metal, and I wo

Martin - I'm no 7854 expert, but I've been poking around in a few lately, and the manual has been my bedtime reading material, so I know just enough to be dangerous. That being said, a few thoughts: F

Right - I don't think it knows if it's good data or bad data, only that it got filled up. I'm haven't figured out how yet, still making my way through the manual. I know it's also counting sweeps, but

Nick - The alignment pattern working would seem to indicate the CPU can read & write RAM just fine, nor are their issues from the CPU to the DACs. I'm pretty sure the digitizer writes directly to RAM,

@Albert - No big (or any?) changes to the sampling system between 'old' and 'new', so I am genuinely flummoxed about why I'm getting different results in terms of how fast a complete acquisition can h

Albert - Yep, those are the steps I'm following. Oddly though, my 0.5ms/div works as reported at 512 P/W, and fails gracefully as described at 0.2ms/div, but at 1024 P/W, it works at 2ms/div & fails a

Hi Albert - Are you doing single-sweep Acquisitions with the 7B87? Single-sweep uses the 7B87's internal sample clock, and I just checked on mine and confirmed that at .5mS, the acquisition works fine

Right - that sounds like a set-up error on my part. I didn't think I even have the 0 bit set up in that group, but I must have made a mistake. I'm looking at addresses now, since I've only got 16 chan

That delay is generated by C172. Maybe one of the gates in U179 is stuck high? In either case, that shouldn't impact the ability to troubleshoot the boot issue if I've got the reset wired up (right?).

On power-up, PUP goes high immediately high and stays high... OK, making my way through the PS docs... damn, I was hoping this wouldn't take me back in there. Yep, that works as expected

Interesting... The front panel lights extinguish when I press reset, and illuminate immediately upon releasing the button. The 'Busy' LED stays illuminated at all times. I just got the edge connector

One thing to note - All lights illuminate immediately. The manual seems to indicate that it takes a few seconds to indicate an error code, but even when I was getting the bad ROM light pattern, it was

Rigged up a reset and it's helping. I won't really be able to tell what's going on at startup until the edge card connector arrives and I can look at the address lines, but I can tell by looking at th

yep - you called it! Old ROMs in, all lights on. Haven't broken out the LA yet, but scoped the test points on the ROM board, and am seeing activity on the chip select test points. It's clearly in a pr