dukes909

Well shoot, i am in a hurry to get my 800 running again, lol! Having to wait on a magazine from Germany, booooooo.

Thanks. I emailed to ask but there appears to be no online PDF version..?

Are there any more details on ClausB's mod or has anyone else replaced 4116's with 4164 in an 800? I see the schematic but I am not confident I could build it off of that. (I know I am in trouble when I don't have any idea what Φ2 is or any of those RS4, RS5 & NAND gates!) I see one post says "Look for complete modification instructions in an upcoming issue of pro(c) ATARI magazine!". When I search "48k" on the Atari magazine site I get no results.

It isn’t clear to me if the boards that have non-4116 chips are shot or if they will work once I replace the 7812 voltage regulator. If they are dead, I found a source for 4116’s however they are 150ns instead of 200ns that I have now. Will they work?...will they all have to be the same speed? cheers dukester

Thanks I found some at Jameco and Mouser! Well shoot on the 810, but at least I have the RAM part figured out. Are they likely blown or just not working with the high voltage?

Does the 810 drive use the 12V from the 800? Wondering if this is why I have been having problem with drives as well.

Now I just have to find one....

Argh, I didn't scroll up far enough to catch that again. Thanks. AND it explains why my colors are off, COOL!

Thanks! Does the 800 need 12V other places though besides the RAM chips?

Also, interestingly (!), the chips on the good (working) card are 4116's (although there is 1 errant 5290 on that board) like you said! The other cards have either MM5290 or AM9016!

Ok so I checked the voltages on pins 10 and 12 of the SIO port. pin 10: 4.96V pin 12: 18.38V Umm, so is the 18.38V the problem, and if it is how do I fix it? Thank you for helping!

Before I tear this apart, wouldn't the fact that 1 card works in the first RAM slot indicate all 3 voltages are getting to slots correctly, or is the voltages of the three slots independent of each other?

All the RAM cards I have are 16k, and I was only using the first slot past ROM to test each cartridge.

I haven't. Where do I check this? Thanks!

So I identified a 16k module in my 48k 800 that was bad. Ok. I bought another 800 off of eBay that had 48k working in it when I got it. I swapped in a card from the new 800 into my original 800 and I get a green screen, won't come on. Take that card out and go back to 32k. I take out all of my original memory and try them in the new 800 - 32k ok. I now try 1 16k card from the new machine in my original 800...nothing but green screen. WTH. I try it back in the 800 it came out of..same thing, doesn't work. I basically go through every card configuration and nothing works except my original 2 16k modules. WTH again?? I take a day off from it come back tonight, now only 1 16k module from my original 800 works. WTH!!! So out of 5 working cards that I started with, only 1 works now. DISCLAIMER: I wear a static strap whenever I swap these things in and out; I don't see how I can be causing it. So barring that, is there some way my 800 is destroying these modules? GGGRRRRR Dukester

Further troubleshooting: I have narrowed this down to the 6532 PIA chip C010750-03 , mine is marked 8236. Are these still available?

So I bought another 810 drive to hopefully diagnose what is wrong with my drive that is not reading disks. The condition of "new" drive was listed as "untested". As it turns out, when I powered it up, the head did not move back like it is supposed to. Instead it remained stationary and the drive spindle spins forever. Ok, so my "old" drive at least worked in that regard. So I take the sideboard card(s) out of my old drive and put in the new drive. The new drive works with this set of cards and can read disks - YAY ? !!! I narrow it down a little further to the main sideboard and not the daughterboard or whatever it is called that is smaller and snaps onto it. (Yes I know I now am trying to fix the "new" drive instead of my original one but, one thing at a time). Pictures of the 2 cards below. The "new" sideboard is the one with the blue "C" sticker (this is the one that doesn't work) - the one with the orange "C" sticker is my old card and is the working one. So my question to the experts here is: do I now look for a working sideboard card OR do I test each chip to narrow it down further? Are these old chips even still available? (As a side question, I guess the components C133 - C141 are capacitors? They look really weird compared to what I am used to (cans) especially C126 on the blue sticker board)... Cheers Dukester

I have deoxit but the spray is messy and I don't have a light touch with the spray button..lol

Thanks. Is isopropyl alc ok or Deoxit like I did for the card pins?

At this point I am looking for another 810 Tandon type drive that is working to swap parts with to figure this out. I have cleaned the card pin connectors and reseated them, the belt is intact and in good condition, and the head has been cleaned. The R/W head moves all the way back on power up and stops where it is supposed to. The drive head advances when trying to do reads (disk directory) or formats. But it doesn't get past that point. Running speed tests spins the disk but no information is returned on the speed.

Reseat the cards? I’ve done that.

So it is trying to check the speed but nothing ever gets reported back. Any ideas? Usually I get a 144 or 128 error if I hit BREAk to stop the program.

ok I changed the 810 and set it to 1 but when I run this it just does the grindy thing near the edge of the disk.

ok I changed the 810 and set it to 1 but when I run this it just does the grindy thing near the edge of the disk.

This runs but it tries to use D1 where RespeQt is instead of D2 where my 810 is. I am looking at the listing but it is beyond me how to set the drive to 2.lol