Get most of the solder off and then stick a loop of very fine wired behind the pin, heat & lift!
You mentioned $1200 - that sounds expensive for proto boards are they huge or special in some way?
That 200mV spec (RMS!) on the cheapies is a bit much (they're switchers), but for $50 apiece they'd be fine to have a few around. My Rigol is rated at even better, but it's 20dB more expensive again.
It's nice to have some of the old linear ones around that don't have HF noise on the outputs, but eventually there's usually a switcher in there (often followed by a linear for sensitive stuff).
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
o put it
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That looks like the Mastek supply. And yeah to measure the ripple I needed an amp between the supply and 'scope. I'd stick with the linear regulator.
George H.
No, just ordered 10 boards. They are abut 2"x2", and have about 60 components. Ordered them with all SMT components on them, since several of the ICs are fine pitched, and my hands are not as steady as they once were...
I got bids from half a dozen vendors, and this one was best by a few hundred dollars!
Charlie
Always get a couple of bare boards, "solder samples."
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
rating.
I bought one. They gave me a tracking number. Then they said they are out of stock (regardless of what E_ay says) and will refund my money. I said I would rather have the PS, but they said no more will be available.
Charlie E. schrieb:
Hello,
it test the new boards first for the isolation resistance between power and ground. If there is a short, adding parts is useless. I suggest you test all other boards first, maybe all of them got the short. If they all got the short, you can find the location of the short using high current, of course with a board without parts. When you found the short, maybe you can repair all other boards with a sharp knife.
Bye
So, just a note to everyone. Looks like all these processors are toast. Evidently, just scoping them with my DMM to see the resistance was enought to blow the PIC processor. Going to see if my board house can do rework, and replace the chips with new ones with the pins already lifted...
Charlie
I suspect you have another problem. Those chips can take more current than any sensible DMM will put out. A power supply across those connections might damage them, but not a DMM.
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
I've got the same supply. I removed the regular pots and installed 10 turn pots in their place. Took a little work, but well worth the effort. (Had to drill the panel holes a bit larger.) The supply works well - the only problem I see is the current meter showing 20 mA (no load) as the minimum. i.e.: If your load draws 10 mA, the meter show 30 mA; if you don't connect a load it shows 20 mA.
Ed
There's probably a pot that you can adjust for that...
Another update on this problem. As you may recall, I had found the short, repaired it, but was still unable to program the MCUs. I sent the boards back, and replaced the chips, and they still wouldn't program. Finally, I put the scope on the programming connections, and could see the clock and data lines were changing, but the programmer wasn't seeing it. I finally decided it must be my programming cable, so I ordered an 'official' Microchip adapter for my programming header.
It arrived this afternoon, and I am now able to program my boards, EVEN the one that I didn't replace the chip on!
As far as I can tell, on the programming cable that I had built, the program data line, even though it passed every continuity check I could think of, was not connecting to the programmer. I can only assume that the programmer didn't like the RJ11 connector that I was using, and didn't make good contact. ARRGGH!
Now, I have a lot of debugging and troubleshooting ahead of me!
Thank you all for your help!
Charlie
They can get kind of fussy about long cables. I don't like to go over about 6" (150mm).
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
For this one, I took another cable, and just put a new RJ11 end on it. I think that the RJ11 socket on the ICD3 is a little tempermental. I have had problems with them before not making good contact on some connectors.
Charlie
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