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

Hello Bill - I saw your message about extenders. I need to see how many parts I have, but I am pretty sure I have everything. I'll check today some time and let you know. Do you want one extender or t

FYI, and sorry if you already have this info, that should be a 2N3724A.

Hi Team Tek - I am considering upgrading my scope. There are a bunch of TDS5104s and TDS7104s on Ebay, and other than the OS, I can't see any difference in their specs. Does anyone know how these two

InstaVu seems like the right place to start, but I don't know a way to trigger properly (on both edges). Has anyone done this on this vintage scope? Thanks Dan

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 have parts for extender kits on hand (for TM500 / TM5000). I have been emailing people that are on my wait list, but if you haven't heard from me and would like a kit please contact me off list. Kit

Not sure why the link doesn't work. If you search it doesn't come up, but I suspect that's because they are out of stock. Here is the link again, just in case: https://www.amazon.com/dp/B078SY3X1H If

Hello Tek Heads - I made a bunch of extenders, thank you to those that purchased through my Amazon page or through this group. I hope everyone that bought one is happy with them. I am out of PC boards

Try here. Not a lot of different part numbers, but a good range of voltage / current / power. Also includes diodes. This is a “semiconductor kit” with transistors and diodes: https://joeknowselectroni

Hello Tek-heads - Thanks to everyone that bought these TM500 / TM5000 extenders. I had a lot more demand than I expected, so I am sorry that some orders took some time to fill. These are yellow (I wan