We are having trouble communicating with the boards in our system, and believe that the problem is in the converter board. IC U1 seems to be very hot. Does...
Hi Paul, When an IC gets hot, it typically indicates one of two things: The IC's internal thermal protection is preventing IC damage by causing it to shut...
Paul: I'll add to Marc's list. I assume that it was working? Was anything new added to the C/MRInet? I would pull the output line off and see if the heat goes...
Hey List I had a rough holiday weekend. It got HOT in the basement, so much so that Remley was frying eggs on the C/MRI Compaq Deskpro computer and the steam ...
Chris, I show the 74HC540 available at Jameco as of now and it is cheaper than the 74LS540. It is compatible. Joe Kasper ... From: CMRI_Users@yahoogroups.com...
Chris: While I was checking my inventory of LS540 spares... one... I see Joe has suggested the other alternative... There are many families of ICs that could...
Another item we are starting to see is that the ROHS compliant (parts containg NO LEAD) are being required. And they are a slightly different part number, but...
... Chris -- I would do the 74HCT series instead. "T" means TTL compatible. If your whole board has been converted, then 74HC is OK. 74HC/74HCT-series are...
They didn't offer me that as an compatible alternative when I talked to them. Dratz! _____ From: CMRI_Users@yahoogroups.com [mailto:CMRI_Users@yahoogroups.com]...
Thanks! You answered a question before I asked it!!!! That being, can you mix HC and LS?? My gut said "No" and I'd replace the whole lot to make them equal. ...
Chris: The differences in the logic families are basically speed and how many other devices will they drive in terms of other chips (gates). The SMINI in...
Okay - then Mouser or Digikey has it all in stock. I just had two LM324N's blow tonight, one more blew last night. Random parts of the layout, one section on...
How are you powering those boards. I run a regulated 12 VDC to all SMINI locations and then put a LM7805 regulator on a heat sink right by each board. I use 12...
Chris: Jim brings up a good point about power, at least checking what you're supplies are running at. With extreme heat utilities brown down, reduce voltage,...
Futurlec has them in stock for $0.58. ... From: CMRI_Users@yahoogroups.com [mailto:CMRI_Users@yahoogroups.com] On Behalf Of Chris Ruhl Sent: Tuesday, July 06,...
That was the first thing that I checked and checked repeatedly over the afternoon. The voltage never went out of the 12.01 to 12.10 range. My last check was...
Thanks! I have to add them to my list. I got a bunch from Digikey for about that price. I chose Texas Instruments for the manufacturer. Jameco often batches...
The last time I ordered, I told Jameco rep the part was not listed in their catalogue. Now we know why. Don Ps you will now see most of my posts from...
You are correct -- I was being ambiguous in my note -- The SMINI's are happy now since I replaced the bad input IC's -- I was referring to the three blown...
I did check the volts on that end, too. 5.08 volts constant. ... From: CMRI_Users@yahoogroups.com [mailto:CMRI_Users@yahoogroups.com] On Behalf Of James...
Yup, Digikey put the 74LS540 out to pasture but they have plenty of the 74HC540. I ordered a few of them. Mouser told me that they have not discontinued the...
Hi, Earl Yes, my electronic tech pals asked me if I had sockets on the boards! If not, install them, said they! I thought back - years ago, I had DC OD's in...
You're right - I knew the original OD used something different than DCCOD but remembered wrong! I am, though, at a loss with things. I obtained a new batch of...
Hi Chris, Looking at your comments and the DCCOD schematic, everything works left of R9 and L1 including U1. Parts to the right could be in question. The parts...
Thanks, Marc That's a help. I much appreciate it! I'm now down to two bad DCCOD's from the original four. One had a bad Q1 I was wondering about Q5....
