I'm trying to fix a 128k Analog Board and would like to know if I can test the diodes and resistors and capacitors without removing them from the board? i have a digital multimeter.
C20 and C21? Do you mean capacitors? Yes, it would be the same procedure as I mentioned above, but be aware as I mentioned before, a multimeter can only tell you 1 of 2 things about capacitors:Thanks GnatGoSplat!
How about the two big diodes at C20 and C21, how do you test them? is it the same procedure as you mentioned above?
Have you used an ESR Meter at all? ISTR, 4sPhoto saying that he's had great success using one.I've personally had very little luck testing capacitors in-situ . . .Maybe that's just my experience, but I wouldn't trust a multimeter reading to diagnose a bad cap.
Thanks for the links, I just downloaded the assembly manual, does it pay to spend the extra $40 to get it assembled . . .You can also buy it here: http://www.flippers.com/catalog/index.php?cPath=3I have its predecessor, definitely a valuable tool for repairing anything using electrolytic capacitors. Although if this is the only thing you plan to repair for awhile, rather than buying a meter, it might be cheaper to just replace the caps.
If they're diodes, you can check them the way I described with the diode check function - meter will read voltage drop (usually 0.3-0.6V) in correct polarity, infinity (nothing) in reverse polarity. If either appears shorted, then you'll need to desolder one leg or remove it and test out of circuit to confirm it's bad.Oops sorry, I mean the two big diodes at CR20 and CR21. The ones with heatsink. How do you check/test them?
I assembled mine myself, but I enjoy both assembling electronic circuits and saving money so it was a no-brainer decision! If you're fairly adept with a soldering iron and enjoy spending time assembling things, I'd recommend getting the kit and assemble it yourself. It's fun!Thanks for the links, I just downloaded the assembly manual, does it pay to spend the extra $40 to get it assembled . . .. . . or is it a good way to earn a few credits in the Electronics School of Hard Knocks for a negative $40 tuition payment? )
No, just the capacitance setting on my cheap multimeter. And looking at the prices of an ESR meter I think I'll stick with that. ;^b
I'm a tool user/collector/maker, so I'd rather do the ESR Meter project than soldering all my caps en masse!No, just the capacitance setting on my cheap multimeter. And looking at the prices of an ESR meter I think I'll stick with that. ;^b
(I could replace every capacitor on all of my Commodore PETs several times over for the price of the cheapest one I see.)
I've got half a dozen (at least, and I can never find the one I want : ) ranging from a $5 Harbor Freight Digital up through a nice Compact. Beeping CrapShack Digital and a really nice Analog Meter from the PhoneShack . . .Maybe a better meter works moar better. I have a *fantastic* $20 China Special.
If you've got an old PC or laptop to spare, look out for an old Tektronix TWD120. It's a SCSI-based 100MHz scope, controlled by software on the PC. System requirements are very low, the software was designed for Windows 3.1, but it works in all newer 32-bit Windows that I've tried. The nice thing about a PC-based scope is you can capture images of your waveforms. I've seen them go for next to nothing on eBay in the past.I still haven't found a SillyScope for under $100, but then again, I've got a nice Logic Probe from Radioshack that's mostly untried for . . .. . . waaaay longer than I'd like to admit! :I