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ICD Multi I/O overheating


ratwell

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My original ICD Multi I/O (#0056) was prone to overheating. I had sent it back to Harker and Co. back in the day and when it came back to me repaired it still overheated. I just found the receipt from 1988 which brought back all these memories...

 

My solution at the time was to remove the black plastic side pieces where the ports were located and run a small 12V fan to blow air through the enclosure. I was pretty disappointed in ICD at the time and especially by this extra fan noise in my computer room which just added to the PC power supply fan noise that was powering my hard drive.

1) Was this a common problem with early units or just mine?

2) What was issue with the design and how was it fixed?

BTW, does anyone have #0056 in their possession?

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Mine was a later unit, but it came with a 9v DC PSU, which would have only used one side of the full bridge rectifier circuit. I was lucky to never have overheating issues in 5+ years of continuous use, but it would have been smart to use a 9v *AC* PSU to even out the diode usage to 50% duty cycle each.

 

Found the pics, guess my units are much much later production units (1MB 0953, 256K 1569) but definite scorch/browning under the diodes on the PCB's. :)

 

Unfortunately my friend who was the original owner of the 256K unit added some makeshift ventilation to his case out of frustration.... ?

 

256k.thumb.jpg.e11b781d0a011036eea482d1639b2eec.jpg

 

 

 

507788330_1MBMIO0953.thumb.jpg.d8250a96a0bc8be97e51c4bc0cc3fe5e.jpg392674223_256KMIO1569.thumb.jpg.8128181e60bc454eb938af0dddb4746c.jpg

 

ps: There is a Canadian 1MB MIO posted on ebay yesterday has crazy bidding already, seriously nudging me to list one of mine! :

https://www.ebay.ca/itm/154335357869

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35 minutes ago, Tillek said:

Not sure if it was just the 1mb ones that were a problem.... I had a 256k one that I think I fried that was running TVAG BBS and I never noticed it running hot.  Love to figure out what is wrong with it and get it fixed though. :(

 

 

Mine was the 1MB model and I was running a BBS Express! Pro on it.

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37 minutes ago, ratwell said:

My original ICD Multi I/O (#0056) was prone to overheating. I had sent it back to Harker and Co. back in the day and when it came back to me repaired it still overheated. I just found the receipt from 1988 which brought back all these memories...

 

My solution at the time was to remove the black plastic side pieces where the ports were located and run a small 12V fan to blow air through the enclosure. I was pretty disappointed in ICD at the time and especially by this extra fan noise in my computer room which just added to the PC power supply fan noise that was powering my hard drive.

1) Was this a common problem with early units or just mine?

2) What was issue with the design and how was it fixed?

BTW, does anyone have #0056 in their possession?

 

You can see in the internal images in the post by @Nezgar that the traces to the rectifier diodes are wrinkled where they have partially delaminated from the PCB on the 1MB model. My 1MB MIO is similar, including the wrinkled traces, but is earlier manufacture and originally came with solid end panels.

 

I sent this MIO to ICD for repair in the early 90's, when it was returned they had replaced the rectifier diodes, possibly the voltage regulator, and the end panels were now perforated. ICD also removed the following parts intended for use with the 80-column upgrade: J5(second PBI header), J8(DE9 video port), J10(10-pin header), VR2 and related diodes/capacitors. I notice all of these except J8 have been removed from Nezgars 1MB model, likely because it came with perforated end panels. The image below has the areas where components were removed indicated in yellow.

MIO-0679.thumb.png.1333c079f02f402a54843ee6672f855d.png

 

IIRC when @MEtalGuy66 built his updated version he used wider traces to the diodes/voltage regulator, and also elevated and spaced the diodes further apart to aid heat dissipation. The case he used was from the original ICD supplier but taller, with ventilated end panels this would increase the area for the heat to escape. He also updated the 32 x 41256 ZIP DRAM to a single 30-pin SIMM which would have reduced power consumption

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9 minutes ago, _The Doctor__ said:

posts like this are almost always followed up with and ebay link to some ridiculous ebay auction, that start shortly before during or after the post

The OP didn't post the link about the one listed yesterday by a seller in Victoria, Nezgar did. 

Only been listed a little over 24 hours and bids are already over C$600

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19 minutes ago, David_P said:

My 256K MIO is older - SN 1588.  No video port (although there are the pads on the board).  No overheating issues.

I think yours is one of the newest based on the high SN and heat mitigation mods.

 

19 minutes ago, _The Doctor__ said:

posts like this are almost always followed up with an ebay link to some ridiculous ebay auction that start shortly before, during or after the post.

Guilty as charged! Hehe

 

6 minutes ago, BillC said:

one listed yesterday by a seller in Victoria

I used to network my pro BBS (node 244, Maple Ridge BC) with the Pothole BBS in Victoria so I messaged the seller to inquire if it was by chance the MIO used to run that BBS. Alas he replied no, but he recalls that BBS name and having dialed into it.

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Having a good laugh at the moment.  wow... and it's got a long way to go... wonder if it's going to really get paid at the end or if it will be one of those oh the other guy backed out but I'll sell it to you for your last bid made before the guy stiffed me type deals...   those are the ones where I say no, but if you go all the way back to the last bid before he started bidding then yes! certainly. :)

 

as for over heating... yup, always beefed that stuff up and made sure to ventilate em...

Edited by _The Doctor__
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If you hook an external 5VDC PSU to J7, the regulator and rectifier will be bypassed and the MIO will run much cooler. If its a 1meg model, make sure your PSU is capable of doing at least 1A sustained, preferably more..  You'll have to rig an inline switch if the PSU doesn't have one, because this also bypasses the power switch on the MIO. This is what smart BBS sysops did back in the day after realizing that even extra fans wouldn't save the MIO's pitifully underrated PSU components from eventually cooking themselves, during 24-7 sustained useage..  

 

J7 pinout:

1&2 9VAC circuit (do not connect anything here)

3&4 9VAC circuit (do not connect anything here)

5&6 GND

7&8 5VDC

 

 

note: make sure your MIO has the 5V PLL upgrade. In other words, it has to have the newer U19 IC that runs on 5VDC. Otherwise, you will need an additional 12VDC supply to pin 16 of U19. If your board is missing VR2, then it has the upgrade. If VR2 is populated, then it does not have the upgrade. 

 

 

 

 

Edited by MEtalGuy66
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2 hours ago, BillC said:

 

You can see in the internal images in the post by @Nezgar that the traces to the rectifier diodes are wrinkled where they have partially delaminated from the PCB on the 1MB model.

That's must be what happened to mine.

Quote

I sent this MIO to ICD for repair in the early 90's, when it was returned they had replaced the rectifier diodes, possibly the voltage regulator, and the end panels were now perforated.

Mine came back with solid panels. I wonder how many units they repaired before they figured that out.

Quote

IIRC when @MEtalGuy66 built his updated version he used wider traces to the diodes/voltage regulator, and also elevated and spaced the diodes further apart to aid heat dissipation. The case he used was from the original ICD supplier but taller, with ventilated end panels this would increase the area for the heat to escape. He also updated the 32 x 41256 ZIP DRAM to a single 30-pin SIMM which would have reduced power consumption

That was going to be my next question.

Thank you to everyone for all this background.

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Just now, ratwell said:

Mine came back with solid panels. I wonder how many units they repaired before they figured that out.

You could always make holes in the solid panels you have. I think if holes were at the top of one end panel and at the bottom of the other the heated air escaping might create airflow through the case.

 

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I did some more digging through my box of old paperwork and it seems I was wrong about sending the Multi I/O for repair.

I had to send it back twice!!!

 

Thinking back on this now, it was a pretty big expense for a kid funding this hobby with his paper route: (1MB MIO, R-Time 8, Adaptec 4070, 20MB HD, PC Power supply = $$$). Add in the exchange rate, all the back and forth shipping costs and customs duties...

Judging but the dates, it took about 8 months from purchase date to get a stable system from ICD which still needed fans blowing through it.

I know this was about the time I sold everything to local club members and shelved the BBS, sadly.

 

ICD MIO #0056 Repair Invoices 1of5.jpg

ICD MIO #0056 Repair Invoices 2of5.jpg

ICD MIO #0056 Repair Invoices 3of5.jpg

ICD MIO #0056 Repair Invoices 4of5.jpg

ICD MIO #0056 Repair Invoices 5of5.jpg

Edited by ratwell
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24 minutes ago, ratwell said:

Judging but the dates, it took about 8 months from purchase date to get a stable system from ICD which still needed fans blowing through it.

That was a little over 7 months from when you purchased the Adaptec 4070 and a couple of other pieces(probably SCSI ribbon cable + power splitter) to when ICD returned the properly repaired MIO, the receipt for the MIO itself isn't included in your post.

 

I kept using mine up until I purchased a Pentium 100 clone in January 1996, I had a 40MB ST251 HDD attached for about 5 years at that point. While I stopped using it, and much of my collection went into storage I never got rid of any of it except a modem and a printer, neither of them Atari brand.

I sometimes consider upgrading the MIO firmware and connecting some newer SCSI drives, the V1.4x firmware available at rasterline.com supports Seagate drives up to 73GB. 

 

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1 hour ago, BillC said:

That was a little over 7 months from when you purchased the Adaptec 4070 and a couple of other pieces(probably SCSI ribbon cable + power splitter) to when ICD returned the properly repaired MIO, the receipt for the MIO itself isn't included in your post.

Right. I haven't found that receipt yet. I only have a vague memory of buying the MIO beforehand. There's a Nov 1987 written in my handwriting on the box (why did I keep these boxes!?!) which coincides when I moved. Maybe I did purchase it in 1987...

Every other ICD product I'd bought impressed me with its utility and reliability and the MIO's feature set on its own was incredibly impressive.

I wish I'd been able to figure out a workaround for the overheating problem at the time. As ICD was unable to fix (twice), I felt there was something seriously wrong with the design and I didn't have the background to debug it.

Just listening to this now:

https://ataripodcast.libsyn.com/antic-interview-125-tom

Edited by ratwell
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This MIO for sale on eBay is one of mine. I have two of them, and really don't need two.  I've offered stuff for sale through Atari Age directly in the past, and that has turned out well for me, but with the MIO, I really don't know what it's worth so wasn't sure what to ask for.  I figured I'd let the free market decide and posted it up on eBay.

 

I remember these over-heating back in the day, and many folks that I saw running them took the end plates off entirely, and setup fans blowing over everything as was mentioned.  I was always impressed with the MIO and the RAMdisk capability was great with the 1MB version, as well as the ability to run faster modems than the SIO modems available from Atari.

 

Of course we all wanted the CSS Blackbox, but I don't believe I ever even saw one of those BITD.  Maybe one (?), but I didn't get to play with it personally.

Edited by Shawn Jefferson
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My original 256k was #0013 and it overheated.  I took the panels out of it.  I no longer have that one.  But for $500 US, maybe I need to start selling my other ones off.  I have 1 ICD 256k, 1 ICD 1M  and 1 MG66 1M.  The 1M ICD was updated by MG66 and he sent me the chips to do the 256k.  I might sell the two ICDs for the right money...

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I have an ebay alert setup for ICD MIO and various faxcimiles of the same .. didnt get notified.. based on the price you guys are talking about it wouldn’t have mattered anyway. I wouldnt pay THAT much for a freaking amiga 600 which I also want badly ... ugh.

 

great topic - and some awesome info and throwback memories.. Thank you!

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