Make sure to use a good contact cleaner / lube and clean ALL of the controls! Dirty switches can make for very interesting symptoms. I once acquired a 475 that almost did nothing - cleaning the contro

Thanks, yeah I see the data sheet. I was hoping to know exactly how it's made. What's inside. The real scooby.

Hey team - I changed roles at work and I ran into a new animal called a rail probe. I have never seen one of these things before, even though I have been doing analog and power for a few decades now.

This has been taken.

Sorry the JM memorial extender has been taken.

This has been spoken for -

I used this for parts - the HV transformer and one IC (at least) are missing. No idea what the condition of the rest of the board is. I don't have any TDS scopes any more so need to find a home for it

I owned a few TDS scopes, a couple of 744s and then a 754. Don't have them any more. I have the front end module, with is the PCB assembly with the four front end hybrids in the metal cover. It has th

I don't have the scope anymore, and had replaced the floppy with USB. If you can use this, free for shipping from 78735. Dan

I have a Jerry Massengale 7k extender here that I don't need. I forget how I got it from him - I think we traded something at one time. Happy to pass it along free to anyone in need, for cost of shipp

Thanks Monty! Very generous to put it up for us to use. I need to check all my mainframes to see if I need any - I'm sure I'm missing some. If I print them I'll let you know how it turns out. Dan

Thanks everyone for the endorsement! I am really happy they have been useful. I don't have any more parts for building more, though. My cost for parts is about $20-$25 for each extender, with a purcha

I've had a couple of TDS7x4 scopes with issues on that board. Below are some notes that I wrote up once for the group. Also I have a schematic that I got somewhere for a TDS544 HV board, and I was abl

I am getting this scope - will pick up later in the week or over the weekend. I don't need it but would like to find it a good home. I would ship from 78732 for actual shipping cost (plus the $20 purc

Anyone looking for a replacement tip for a P6139A: Cal Test Electronics CT3667 is a perfect alternate. $22.50 on Mouser. I just got two, compared performance (rise time and ability to compensate) and

Using the two-probe method that Mike suggested is the usual way of making a differential measurement (when expensive diff probes are not available, or when the voltages are too high for them). One thi

I had a 485 that hiccupped when I got it. The way I determined the bad rail was to look at the turn-on and turn-off edges while in hiccup mode. One rail didn't get as (proportionally) high when ON, an

Hello - I am out on business travel Sunday through Friday (4/7 through 4/12) this week. Replies may be delayed. Sorry for the inconvenience. Best regards Dan

Hello - I am out on business travel Sunday through Friday (4/7 through 4/12) this week. Replies may be delayed. Sorry for the inconvenience. Best regards Dan

I've owned several P6139s and they have all used the larger (3.5mm) cartridges. I just purchased four like-new ones, and they all use 2.5mm cartridges. First question - any chance these are counterfei