| Electronics > Metrology |
| Keithley 155 restoration project |
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| Rax:
I've recently grabbed this null meter - I wanted one for quite a while, as in my opinion, it may be the best of any options available. This is due to the SS chopper, form factor, reliability, options. I like just about everything about this instrument. This one's in just about pristine physical condition - if I didn't know anything about it, I'd think it's NIB and just came out of the box. Even the batteries inside are original, in perfect shape (though... we'll see, maybe there's surprises at the underside of the holder?...), and they only fail marginally (one polarity is a bit under 8V...). One thing I need to sort out is the mode switch at the back of the 1554 power supply module. The switch is very reluctant to move. I'm also reluctant to use contact cleaner or even heavier lubricants (I think the switch is moving on dry in a way that makes me suspicious it will fail soon), from the perspective of leakage. The unit is advertised to not present any degradation of its floating characteristics and any leakage to AC line. Any thoughts would be appreciated on how to handle this. Also, I'd greatly appreciate any specific files or info on the 1554 power supply module. Particularly a schematic would be nice. I'd like to both rebuild it, but also sort out the switch smooth operation issue. The schematic would help assess the impact of treating that switch with contact cleaner, I wager. I'm currently printing a 3D holder from this forum - thank you lowimpedance!! - and will replace the batteries with 9V lithium batteries, which I assume will hold forever and, even more importantly, not leak! Thanks a bunch! |
| Rax:
A couple more pics. |
| andrewtaylor:
Congratulation to your new meter -- really in great shape. I am shure you will enjoy to work with it, it is a very reliable instrument. |
| Rax:
--- Quote from: andrewtaylor on November 15, 2024, 06:55:56 pm ---it is a very reliable instrument. --- End quote --- Thank you very much - that's where my efforts are currently focusing - making sure it remains reliable and I extend its life even further. I may examine a selective recapping, 3D printing (currently underway) a housing for modern 9V batteries, maybe a couple other things. It'd be great if I can get a hold of some materials on the 1554 module though. |
| HighVoltage:
Your 155 looks very nice This was my project https://www.eevblog.com/forum/repair/keithley-155-null-detector-repair-and-restauration-attempt/ |
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