Nezgar

Would it be possible to hide the screen buffer under the basic rom in XL/XE? Then at least for BASIC programs there's no apparent additional loss from the 8K screenbuffer. Handler switches off basic ROM for any changes to the screen, DLI's to turn off basic ROM during screen draw. I guess this could slow down the drawing? I guess hiding it under OS is another possibility, but harder/ slower.

Yes... don't use Satantronic's XRAM tester 0.21.0 - it was updated in 2019 To 0.22.0 specifically to not erroneously detect the 4 banks that mirror the base 64K in a RAMBO type 256K upgrade: http://atari.sk/extended-ram-test-0-22-0-xram0220-xex/ 0.22.0 looks like this on a RAMBO 256K XL - note nothing on $8x row:

Worth a try - but I'd be surprised. XL/XE MMU logic should should automatically override enabling of the internal BASIC ROM with the presence of a cart. They both occupy the same block of memory... Edit: it would be good to hear if anyone else here with a Q*BERT cart and a 130XE can also test and compare result. It may be incompatible code.

These are the "speed limiting" capacitors on a later reversion of the XE motherboard. (they have a "C" prefix for capacitor) C76/C77 exist on every XE motherboard revision i believe, but C103/C104 was in the later revision negating the need for the wad of bodge capacitors on the SIO jack of earlier rev motherboards. Earlier XE motherboards have a wad of them soldered between the ground plane behind the SIO jack to every pin, as seen in @Gitbizy's original post. Edit: and Damb... whomever did the upgrades went through the work of desoldering the eight 1x64 DRAM chips and replacing with 1x256's but didn't bother installing sockets while they were at it! ? Regardless - with these upgrades now identified, you could potentially resell it for a higher price, and acquire another stock XE.

Also visually inspect and clean the contacts/fingers in the cartridge port in the 130XE. I personally have destroyed the fingers in the cart connector on one XE... some cartridge must have caught the pin and pushed it back.... was able to get it back to functional with careful surgery but annoying it happenned, and now I'm paranoid about it happenning again eventually... Especially those catrdiges with hard flat PCB edge connectors. Also clean the cart port contacts/fingers - put a decent amount isopropyl alcohol on the cartridge edge connector, and insert/remove it many times from the computer to assist cleaning the XE side cart port too....

Looking up a few screenshots, it looks exactly the same as the Atari 8-bit version, except with boring grey borders and paddle. What's the difference? Edit: Oh and a fancier brick hit animation...

It should only start rotating screen colours in attract mode after 9 minutes of no keypresses - that's all... If it jumped into self test mode, that would imply "something" happenned .... power glitch causing reset into self test mode or something....

"ATASCII OF THE PETSCII ROBOTS" ?

@SpicyChronos WST / Tandon roms fundamentally only have stepper timing and phase encoding differences - the code should run just fine with either drive otherwise for testing POST, but don't expect a tandon drive to keep up with the WST step speeds. If you arent already - have you tested an EPROM in the 1050 mother board socket with the happy board in place with it's ROM socket empty and 6502 in place? This may help narrow down if the issue is with ROM socket wiring. Of course you'll need a 2732 type eprom to use in the motherboard socket...

Totally forgot about this... and spent the last 15 minutes going back in time on facebook (not easy!!) to figure out who I was in contact with... But I figured it out and shooted a note asking if he can check if there is anything on side 2....

Heh, yeah that mod/hack was specific to the console keys as @_The Doctor__ mentioned... they are tied directly to pins on the GTIA. The extra resistors let a little more voltage through to compensate for increased resistance that XE membranes often develop over time. I like the steps considered though: swap 4051's, swap POKEY. Somewhere in these threads is a matrix diagram that might hint at what interconnects result in "L" ... Edit - here's one:

I have a Happy 1050 with the original ROM still in it's motherboard socket, with a nifty mod where a toggle switch determines which ROM receives power on a bent-out pin 28... the one on the 1050 motherboard, or the one on the happy board. So the original 1050 ROM works just fine with the happy's 6502, at least with a genuine happy board...

Also if internal oil is "gunked up" you may be able to also loosen things up by just manually sliding the whole transport back and forth many times while the drive is off, and see if it moves any better afterwards... Another thought would be to test WST 1050 firmware in the drive, as that ROMs stepper phase encodings always keeps two of the phase coils of the stepper powered instead of just one with regular Tandon firmware - more likely to be able to overcome any physical resistance. However, this will put the transport 1/4 of a track out of alignment in a Tandon 1050, so should be manually realigned if kept permanently.

Yeah, I agree based on the different address, and especially this different logo (MP, not MPI) it also seems to me to be a separate company. I bet theres a completely independant "AAA Aardvark Plumbing & Heating" in each city that has their own phone book too...

@Maury Markowitz How about a service manual? https://archive.org/details/MPI_51-52_Disk_Drive_Product_Manual_1980_MPI

Triple check polarity is correct... and since using a MIDI/keyboard cable be extremely careful not plug it into the monitor port, as it will fit.... And hopefully the wall wart PSU is rated for at least 1.0A output... Other than that ive repurposed a half dozen 5.0V DC PSU's - some with better results than others. Cheap and/or low amp PSU's dont have good filters on the output causing video noise, or undervolt under load causing off-color and some peripherals or upgrades to malfunction.

Micro Peripherals Inc From MPI drive mechanisms in Atari 810's: From inside a Percom AT88-S1: From inside a RANA 1000: That's interesting and confusing that there was also a "Magnetic Peripherals Inc." - I did not know this before, but I found an image from a drive as you say - with a Control Data logo:

Would most probably stand for OmniView XE - an alternative OS with a software 80 columns mode as it's most notable feature. The switch would allow you to switch between the original OS ROM for compatibility, and the modified OS ROM. Here's the manual: https://archive.org/details/OmniviewXLXEManual If you can post a picture of the inside of the machine, we can probably tell you if there are any other things going on in there.

Makes sense if using a double sided disk in a single sided drive -- It's probably trying to read a sector beyond #720, anything past that on a single sided drive will return a drive NAK / error 139 (except technically ED which goes up to 1040...) If you make a single sided double density disk, that should work fine in either drive.

Doesn't the super archiver + bitwriter require removing the ROM anyway? Maybe it needs the 6810 present, but you can probably just leave the doubled RAM module in place for now - at least I know it works fine with the stock ROM. If you have the EPROM version of the US doubler you can just swap in a new 2732 programmed with the stock ROM -- ie Rev L for a Tandon mech / made in Singapore drive, and one referred to as "WST R5" for a World Storage technologies mech / made in Hong Kong. If you have the mask ROM version of the US doubler, you'll need to replace it with a mask ROM stock ROM, or move the JP1/2/3/4 jumpers to support EPROM. 6810 chips can be found on eBay, but be wary of ones from china, I received a batch of 50+ fake/non working ones in the last year... I recall a seller in Switzerland has been reliable.

AH sorry, my bad for not reading everything thoroughly. U10 ROM should definitely not be present with the upgrade board installed. Guessing the connections that connect to switches in @kheller2's board that switch between the ROM's might need to be connected to select "any" ROM, or maybe between all three if there is still a ROM present on the motherbaord in khellers? Maybe there isn't one selected by default with no connection present, and have to trace which of them go to switches and test by putting a jumper across some pins, etc.

JP1 + JP3 when using a mask ROM (as you have - correct!), or JP2 + JP4 when using a 2732 EPROM: I would leave the drive with no upgrades installed to continue to troubleshoot. Start by swapping the U&, U8, U9, U10 chips one at a time into another known working drive to test if any are faulty. If you test swapping the U13 WDC controller chip into another drive, make sure to replace it back into the original drive as each drive is factory calibrated to each chip, and it requires an oscilloscope and some special procedures to calibrate if it is replaced. @kheller2 looks to have a WST / made in hong kong drive + EPROM using JP2 + JP4 -- those all came in this configuration from the factory - but the ROM uses a slightly different stepper phase encoding, which if you use a 3rd party ROM / enhancement intended for made in Singapore / Tandon 1050's will offset the head by a 1/4 track, which is of course undesirable, though we now have a patched US Doubler ROM that can be used in WST drives.

Many clone/replica/pirate happy boards just use a plain 2764 type 8KB EPROM, and move the "banking" function of the original mask ROM (into a 4KB address space) into some logic chips on the PCB.

The Solonoid thing described here: http://blog.3b2.sk/igi/post/Deja-vu-XF551-Navrat-do-minulosti.aspx It helps the drive automatically switch to the correct density by attempting to read a sector from the disk before the Atari does.... otherwise, if you were previously working in DD, and change to a SD disk... the first read of the new disk may fail normally... I don't think "most" people have added this component of the upgrade. The drive originally came with DOS 2.5, which did not use the drives double-sided or true double-density capabilities. DOS XE later came out which did, so maybe your manual was from the earlier set. SpartaDOS 3, RealDOS, SpartaDOS X will also make use of the DSDD capability.

This reminded me of something I saw show up on the local VarageSale for $5.... Tempting. Candle JCTR 123G. Good luck finding anything about it on the Internet...