I was wondering what methods people use to remove the chip off the carrier. I have an ADS chip in my car now, so I have the stock GM memcal to play with. It looks like the chip is soldered in the carrier quite nicely, but hard to get at with an iron. There are little plastic dividers between each pin. Almost looks like the chip is just "plugged in" the carrier, but I am sure is is also soldered.
Anyone try a hot air gun, which you could heat up the entire chip to reflow the solder, thereby lifting the EPROM?

I will most likely replace the chip with a 28 pin socket. Does this make the blue plastic cover unusable?

------------------
Best ET 14.413 @95.57 without
pulling valve covers or manifolds.
Also with stock 2.77 rear end!!!

 

You can't use a standard soldering iron tip ... you need a special small one that is tapered and extends into a very nice small point. Check out my PROM article and I believe I list the one that I ordered which worked great.

Basically, you heat each pin one by one. While heating each pin just slowly pry up on the EPROM until that pin gets free. Then move on to the next pin. Eventually you will have desoldered all 28 pins and the EPROM will come off the carrier.

Tim

------------------
TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's after installing Hooker LT Headers and reducing weight.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

Yeah, what Tim said! I went out and bought a 15-watt Radio Shack soldering iron that had the smallest tip I could find. It was cake taking out the stock chip. AFA the blue cover, it won't even fit over the lowest profile ZIF socket as I tried. I just cut mine in 1/2 and glued the one half above the limp-home chips, although even that really isn't necessary.

------------------
Greg Westphal
'87 IROC 305TPI/A4

 

Thanks for the tips. I looked at work and found a very long, slim tip for a standard Weller iron. That should work. I may try using some solder wick to remove the solder from the pins. I just want to be as carefull as possible!!!!

 

Put the thing in a bench-vise and take a hacksaw to it. Throw the EPROM side in the trash and plug the rest of the assembly back in. Rig up a ribbon cable and a ZIF socket, and you're hot-swapping EPROMS. Or do it real careful like you're doing and replace EPROM with a socket.

 

Although I must confess I haven't tried it yet, it seems to me that clamping an IC test clip onto the top of the stock EPROM, with it still soldered into the carrier, would be the easiest/most foolproof way of reading and writing. Maybe Grumpy can give his $.02, I think he said that's how he's doing it.

 

Test clips are not made for that purpose. Yes I know it sounds like a good idea, but they are designed for troubleshooting and looking at what is going on in the device, like with a scope or logic analyzer. There are too many pins on that EPROM, and it might be easy to bump it and screw up programming/reading of the chip.

I definitly won't hacksaw the chip off!! I might need it later, since I would want to read the code off of it anyways. I think reinstalling a ZIF socket or IC socket is the best method. Once the program is fine tuned to perfection, it could be made permanent (with a IC socket).

------------------
Best ET 14.413 @95.57 without
pulling valve covers or manifolds.
Also with stock 2.77 rear end!!!

 

You can sever the Eprom from the carrier by cutting the carrier in half. I did this, and retained the Eprom half of the carrier for future use. This would be a pretty safe way to get the stock chip out of the way temporarily.

Build an extension ribbon cable with a ZIF on the other end, and you can swap in chips to get it fine-tuned. Once you are happy with the tuning, you can then reprogram your stock chip accordingly, and put the stock Eprom half (now reprogrammed) back in place. No harm done. Clean final install. The carrier can be cleaved without harm. Just a thought.

I've desoldered chips from carriers before, and while it is certainly doable with care, you risk mangling the carrier socket. Additionally, unless you relocate the Eprom insertion location, there is little advantage gained in terms of accessibility. It's very nice to be able to change chips from the driver's seat. Although, if you make the cable too long (more than 2 feet, say), I think you can run into problems. If anyone has experience on this, please feel invited to elaborate...

 

I just desoldered the chip from my stock carrier, and put in a low profile socket. This setup fits under the stock cover, and its not that difficult to remove the chip from. I didnt use a small soldering iron tip, and you can see some marks on the socket, but its minor. Hell, its only plastic.
All the ADS chips I have seen are not soldered, they are just stuck into a socket similar to what I used on mine.



[This message has been edited by madmax (edited November 17, 2000).]

 

Digi-key sells a *header* (like the socket in the ecm), that is like 62 pins.
Your interested in 28.
Sooo, you cut it in half, and then trimm the keys into it. The header has long legs, so spread them out to fit in the progrmmer, and then mod the eraser to take the memcal whole.
Had mine for like 4 years.
For grins, I got the gols version, was like $9 since I'm still using the first one, and still have a spare, things look good.

 

Glad to read everyones comments on this topic. Craig, not sure how you are cutting the carrier in half. Are you cutting between the Eprom and small chips, or are you chopping the whole thing lengthwise, so the edge connector is free from the carrier? Sorry if I don't understand. I see what you are trying to do with an extension ribbon cable. I think just leaving the ECM hanging under the dash, with the cover off, it would be just as easy to swap chips with a socket installed in the carrier.

I am running an ADS Superchip in my car now. I'll have to pull it some day and check out that arrangement. I have my stock GM chip to play with now. I found 2 different types of low-profile sockets at work, and there is a drawer full of 27C128 EPROMs as well. I'm sure they haven't been used. Can't wait to get knee deep into this stuff!!!

 

Grumpy-
You wouldn't happen to have the digi-key P/N for that, would you? I'd like to take a loot at it.

I got a catalog from a place called electronics goldmine the other day, and they have a way-cool inventory. They have a 40-pin test clip on a 18" cable, that terminates to a header connector. It is $8, and I'm thinking it wouldn't be too difficult to solder an IC socket onto the cable, sort-of making an "extension cable" for plugging into a reader's ZIF socket.

Check them out, they've got LOTS of cool stuff. www.goldmine-elec.com

 

I did mine like madmax but, I did not remove the ESC filter over the limp home chips. I used so hot glue between the new IC s****et and the carrier. I did have to cut my cover a little where I put the hot glue, but the cover fit nice and tight.

 

Hmm, catalog is gone.
Hard telling who may have it.
Even looked in kitchen, no joy
Arrggghhhh

 

If I'm looking at the right thing, it is a ribbon cable terminated at each end with DIP sockets. It looks like it could work, but how would you get the pins of the socket to piggyback over the leads on the EPROM? Wouldn't they snap off after trying to do this a few times? Maybe I'm just looking at the wrong cable assembly.

 

I used a Unger Hot Air rework station at work. Its designed to reflow solder with air..just heat up the part and take it off.