4 MB Upgrades

[8bitguy1]

I just spent all weekend trying to upgrade my STf to 4 MB with the Marpet upgrade available from Best. Unfortunately I was not able to get it work. I fried one ST completely and spent 3 hours carefully removing the upgrade from a second ST to get it back to "factory". I was wondering if anybody had any easier upgrades with less soldering... Also if anyone want's the Marpet, make an offer....I'm too frustrated with it to ever try again...lol.

[walter_J64bit]

I just spent all weekend trying to upgrade my STf to 4 MB with the Marpet upgrade available from Best. Unfortunately I was not able to get it work. I fried one ST completely and spent 3 hours carefully removing the upgrade from a second ST to get it back to "factory". I was wondering if anybody had any easier upgrades with less soldering... Also if anyone want's the Marpet, make an offer....I'm too frustrated with it to ever try again...lol.

I've fried my 1040STf with that Marpet upgrade too. So I've just replaced my Stf with a STe I think that best way to go.

[+wood_jl]

I just spent all weekend trying to upgrade my STf to 4 MB with the Marpet upgrade available from Best. Unfortunately I was not able to get it work. I fried one ST completely and spent 3 hours carefully removing the upgrade from a second ST to get it back to "factory". I was wondering if anybody had any easier upgrades with less soldering... Also if anyone want's the Marpet, make an offer....I'm too frustrated with it to ever try again...lol.

 

 

That sucks. I was contemplating trying this, although I'm not so sure of how serious I was, because I'm a ham-fisted newbie klutz with a soldering iron. If you wouldn't mind, can you share a few details of the experience? What got fried? What is the most delicate part of the procedure? How much stuff is there to be hooked up? Was this supposed to sit inside the RF shield, or does it require you to dispense with the shield altogether?

 

At least if you share the tale of sadness, perhaps some good can come of it through others learning of what happened. I think I understand how you must feel, and of course sympathize.

[8bitguy1]

Well, I don't know for certain what exactly went wrong....there is a lot of steps... a lot. Part of the confusion for me was finding out what set of instructions to follow. The kit that Best sells doesn't include the adapter that would sit on top of the MMU so I had to follow the instructions to wire the ribbon cable directly to components on the motherboard. Mostly resistors. I would say I'm somewhere between beginner and intermediate with a soldering iron, so while I thought the task was daunting I figured if I took my time all would work out. I was given 3 sets of instructions for the direct soldering depending on the board revision, unfortunately, the set I had for my board assumed I had a six chip TOS which I did not, I had a two chip TOS. A smarter guy (and a less anxious one) then me would have stopped there, and got correct instructions. I didn't really have an issue with the soldering and I tested it each step of the way, up until you had to solder all the resistors to the cable, everything worked fine until that part. Once you "turn-off" the internal banks of Ram, you can't really test anything until it's all hooked up again to the Marpet. I only ever got a black screen with a white background. I rechecked every solder joint, even redid some just to be safe, but it never seemed to work. The only conclusion I can draw, is that the resistors as they are labelled on my motherboard are not labelled in the same fashion as the instructions. Marpet's instructions warns of this possibility and suggests you call them if that is the case. (Which of course, you can't, this being 18 years after the Marpet was manufactured). So as far as what was 100% wrong, I don't know, either a poor solder joint or differently labelled resistors, I can't rule either out. It does create quite the birds nest in there, it should sit under the RF if your careful though.

 

As for a recommendation...I have a hobbiests understanding of PCB's and soldering and electronics. I would say that is NOT enough to do this upgrade...You might get lucky and have everything work, but its just too hard to troubleshoot if not, and with over 30 solder connections, well....I'll just say it beat me. I'm sure more advanced guys (like in this forum) can do this in their sleep, I just don't get enough practice with the iron or understand enough about making adjustments because the instructions are clearly off a bit (for my revision of motherboard).

 

Anyway...good luck to anyone who tries this...I hope it works for ya.

[8bitguy1]

I just spent all weekend trying to upgrade my STf to 4 MB with the Marpet upgrade available from Best. Unfortunately I was not able to get it work. I fried one ST completely and spent 3 hours carefully removing the upgrade from a second ST to get it back to "factory". I was wondering if anybody had any easier upgrades with less soldering... Also if anyone want's the Marpet, make an offer....I'm too frustrated with it to ever try again...lol.

I've fried my 1040STf with that Marpet upgrade too. So I've just replaced my Stf with a STe I think that best way to go.

 

With the STE can I just plug in the RAM, I think I remember reading the STE has Simm sockets?

[walter_J64bit]

I just spent all weekend trying to upgrade my STf to 4 MB with the Marpet upgrade available from Best. Unfortunately I was not able to get it work. I fried one ST completely and spent 3 hours carefully removing the upgrade from a second ST to get it back to "factory". I was wondering if anybody had any easier upgrades with less soldering... Also if anyone want's the Marpet, make an offer....I'm too frustrated with it to ever try again...lol.

I've fried my 1040STf with that Marpet upgrade too. So I've just replaced my Stf with a STe I think that best way to go.

 

With the STE can I just plug in the RAM, I think I remember reading the STE has Simm sockets?

Yes, it has 30 SIMM's sockets. I did find the instructions to be confusing with the Marpet upgrade they didn't make it clear where the +5v is on the MotherBoard (this is where I'd fried the ST) and it took me 3 or 4 times re-readings of the instructions to figure out some of the installing of the upgrade. I've e-mailed Myatari and Best Electronics to see if they would install the upgrade they both said "NO" I was going to pay them to install it and get it over with, but any way!

Edited June 7, 2010 by walter_J64bit

[+wood_jl]

I've e-mailed Myatari and Best Electronics to see if they would install the upgrade they both said "NO" I was going to pay them to install it and get it over with, but any way!

 

I'm not surprised that B&C Computervisions won't install upgrades. Although I think I see somewhere they're billed as "Atari Sales and Service" I think they're JUST SALES. At least, that's the impression I got in my limited email exchange; I did not directly ask them to install anything, though, but the discussion sounded like I shouldn't.

 

But do you mean to tell me that Best Electronics won't install upgrades? Is it only because you were in possession of the upgrade, already? You mean you can't send in a computer to their "Super Tech" and buy the upgrade NEW from them and pay for the installation from them at the same time? That's strange, and disappointing.

[walter_J64bit]

I've e-mailed Myatari and Best Electronics to see if they would install the upgrade they both said "NO" I was going to pay them to install it and get it over with, but any way!

 

I'm not surprised that B&C Computervisions won't install upgrades. Although I think I see somewhere they're billed as "Atari Sales and Service" I think they're JUST SALES. At least, that's the impression I got in my limited email exchange; I did not directly ask them to install anything, though, but the discussion sounded like I shouldn't.

 

But do you mean to tell me that Best Electronics won't install upgrades? Is it only because you were in possession of the upgrade, already? You mean you can't send in a computer to their "Super Tech" and buy the upgrade NEW from them and pay for the installation from them at the same time? That's strange, and disappointing.

I didn't tell Best Electronics anything about my upgrade I've just asked if they installed them.

Edited June 7, 2010 by walter_J64bit

[8bitguy1]

It would be nice if there were someone who would do this services for a reasonable fee, I agree. I just wish I was more proficient myself, but time doesn't allow me to get that involved with Atari stuff these days. I just really want 4MB somehow...lol.

[Rybags]

There's plenty of people on the Forums here that can do it, especially in Europe or the US.

 

You just have to ask.

[+Stephen Moss]

Once you "turn-off" the internal banks of Ram, you can't really test anything until it's all hooked up again to the Marpet. I only ever got a black screen with a white background. I rechecked every solder joint, even redid some just to be safe, but it never seemed to work.

 

My Marpet upgrade had the socket but IIRC it was being mounted upside down on the MMU a task for which it was not designed thust it did not fit very well and despite getting it "professionally" fitted and considering that they glued it in place it still failed just after the warrenty expired (typical).

Seeing how ill fitting the upside down socket was I decided to cut it off and solder the wires directly to the PCB and I also had just a white screen and nothing else however, as the ribbon cable has no coloured pin 1 wire identifier I figured I had selected the wrong edge of the ribbon cable as pin 1. I desoldered the connections and tried again using the other edge as Pin 1 and it was fine after that, I no longer have the ST but it was still working 10 years later so if your ribbon cable also has no coloured pin 1 identifier perhaps you have done what I did.

NOTE: Soldering to the surface mounted MMU is not a task I would recommend to those who are not good at soldering as shorting pins together is very easy when they are so close to each other, use a magnifying glass to check for shorts before powering up.

 

 

I did find the instructions to be confusing with the Marpet upgrade they didn't make it clear where the +5v is on the MotherBoard (this is where I'd fried the ST) and it took me 3 or 4 times re-readings of the instructions to figure out some of the installing of the upgrade. I've e-mailed Myatari and Best Electronics to see if they would install the upgrade they both said "NO" I was going to pay them to install it and get it over with, but any way!

IIRC the internal RAM is disabled by removing a resistor but they are still powered and so the easiest place to to find 0V and/or +5 connections is by soldering to the power pins of the original memory chips (check their data sheet for correct pin). Did you ask ATY computers if they would fit your upgrade?

[walter_J64bit]

No I didn't, I've forgot about ATY computers. Maybe this topic should be pinned to help out other ST users who might want to use this upgrade.

Edited June 7, 2010 by walter_J64bit