Max/Mel's go bad?

[Jcar1]

I have two identical setups running st19, one with an aux card and one without. All was running well until the last ECM. When the st19 fix and new auxshare were released I was getting the "card not inserted correctly" nag one the setup without the aux card. I diagnosed it to be a problem with the receiver. For the hell of it I reflashed the TSOP and it didn't work so I decided to take the Atmel out and try it in the working receiver and that caused the CNIC nag. I then took the working Atmel and put it in the original problematic receiver and it gave me the CNIC nag. So that tells me that not only is the Atmel fried but the whole max/mel board is not working. Anyone experience anything like this?

[Little Kenobe]

if its a 2-chip emu board then try a different max232 chip or ground out pins .. they do stop working sometimes .. not to worry

[svt98]

I have the exact same problem. Had a power outage a couple weeks ago and lost a receiver and apparently a max/mel board. Reflashed, swapped atmel chips and nothing. One side of it works......the atmel is returning the revision level, but can never get the communications with the computer to get the card number. Weird part is I have two boards like that now. I grabbed another ird and installed another max/mel in it, and same thing. Swapped with old board, same thing, swapped chips, same thing. Have never had any of mine go down before, now I have two. Looks like i better go shopping :eek:

Kenobe what pins are you talking about grounding out? And what does that do ?

[zhakrin]

I had this happen to me once, i replaced the Atmel chip. (luckilly mine is socketed, and i had spares from the HU days)

[ruciz]

they can all fail, I would look into caps. Meter out with DMM. If meter reads they are shorted or wide open replace. Should get a resistance to them, guess 'open' depends on your meter. if read open do voltage check. if shorted well...

if doing voltage check on them it should increase as the caps charge, no power needed to board - meter will charge them. If the cap don't work the maxmel won't work so comm will stop between board and everything.

[svt98]

thanks ruciz, i'll try testing the caps and see if I can find a problem. Barring that, I guess it would be either the 232 or the 4066 chip.

[ruciz]

4066 is a switch, it enables/disables connection to the board. Looking at a schematic you can easily see if the correct pins are making throughput using your DMM when its getting power and your connect link is hooked up (the 3 chip design I have uses the COMM cable to the computer grounds to detect if its to be enabled or disabled - if yours is the same setup it may even be your cable not enabling the board).

I highly doubt the 4066 is your problem - them switches are quite reliable. Usually caps go bad, especially if they are electrolytic. They are only chargepump caps (hold voltage to use when its sending a 5V signal out at RS232 levels) and if one goes bad the whole setup will go awry.

again it could be a corrupt ATmel flash, or the 232 could have went bad too. The parts are cheap, and if they are socketed easy ehough to swap out. if your board is SMT or not-socketed - good luck!

[pecker88]

I have had many max232's go bad. With st19, you can usually tell if the communication looks funky. Have also ruined a max chip by touching it with my statically charged finger!!

[Jcar1]

I haven't tested the caps but the resistors are definatly bad.

[JT]

Almost every issue I've had was a corrupt flash on the atmel. This can actually be pretty easy to do. Static free handling procedures apply when flashing and installing. Other than that, there really isn't much to go wrong with most max/mel boards if they're designed well. Now, some of the one and two chip home built models may have issues, but a well designed board shouldn't have any problems with failure. These things are really dependable. The only time I've seen one fail was when the IRD failed and it burnt out the entire board. It literally smoked and I had to unplug the machine all together.

[Greystone]

This is funny. I was just about to post a question asking the very same thing. See my setup just stopped working, all has been well for 2 years. So I tried a different PC. Nada. Then I tried the comm ports and they are all fine. So I checked the Atmel and it was fine. I even swapped it out but nothing.The green light is on the board but there is no communication with the pc at all.I am not knowledgable enough to soldier caps or what ever may have gone bye bye. Have any one fixed theres ??Mine is from Milli and it has been steady reliable until now.Cheers.

[ruciz]

Mili's 3 chip with the digital switch or just the atmel and 232? The max232 could be gone (spike on the cable could blow it) or the caps that charge it up for the TTL to serial voltage conversion, caps don't last forever.. this would destroy communications. Other than that if they are talking back and forth and the IRD don't respond check for a broken line or a bad switch IC.