So, just stopping the pack discharge is not enough. The cells need to be managed separately as in today's lithium ion battery manager IC's and no cells in series...

Precisely. That's why I remove my 1502 battery packs when I'm not using them. If I don't then sooner or later the 1mA trickle /dis/charge will reverse charge the weakest cell.

Everything you say is absolutely true, as long as you never, ever, ever allow a cell to reverse charge. If you do, it will grow a nickel dendrite through the inter plate insulation, and become a dead

NiCds are more forgiving than the newer chemestries -- they can be cold stored fully discharged. Or allowed to self discharge to nothing, and when needed, you can still trickle charge them back

No, they are all working with minor problems. no reason to cannibalize them.

None of mine are jackfree. I did not know there were different variations like that.

Hello Vaclav I recently acquired a 2217 that was dropped.The case is badlydented and the CRT broken. All else seems OK. If yours is still available, I'd be interested as a parts donor. cash or

did you fix your scope? if so, how? I would replace the SRAM chips (one at a time) . It worked for me in a similar case

Sounds like it has fallen into good hands!

I will try and get hi res pix posted this weekend. Hope to have schematic drawn early next year. This appears to fit a TM-500 series frame. The unit appears to have two channels. The main board id

I've updated TekWiki with the better images. Clearing browser cache & reloading the page may be required to see them. Strange sidebar re the images: In October I thought there were better images but

NiCd cells have a longer shelf life than lithium cells - I believe. The 1502/3 has a nasty characteristic - even when turned off there is a current drain of ~1mA through the chart recorder. If

Very true. However, my own problem with NiCd batteries is I use the equipment so infrequently I would be constantly replacing batteries. I understand this is less of an issue with NiMH and Lithium

I've had a "battery eliminator" that worked in one 1502 but not another. That's one reason I don't like them. Another is that tabbed C NiCd cells are easily available, so the battery can be

Liquid crystals are used in welding masks to darken the weld flash instantly. I think they have other applications in high speed photography, and electronic shutters. So maybe this was part of some

Hi Tom. I have a 2200uF cap, per the TekWiki. Works fine for the 1503, so I expect there is something else going on in the 1502. That's why I'm still scratching my head. I really need to find some

All done I used some sand paper and pressed on the variac windings I carefully slid the carbon brush across it to make sure there is even and complete contact patch on the windings. The stop is

Mark, as Tom said, it can be a transient condition that trips the power supply. When developing a battery emulator for my units, at one point mine would fail when the unit was first powered up after

Hi Dave. I checked the three caps, and C6415 is open. The other two read good on my cap/ESR meter (about 400uF and ESR both < .5ohm). I'll definitely replace the open one, and may do the other two

Worked on many 465B Scopes?