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Member Since 11 Apr 2010
OFFLINE Last Active Today, 2:33 AM

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In Topic: What's the latest Atari related thing(s) you've bought on ebay?

Yesterday, 4:08 AM

Good catch. Looks like I got confused with the next one the seller posted on ebay that I'm watching, not sure where the card edge connector is on it, maybe right up against the case on the back: https://www.ebay.com/itm/222716933109 Maybe coming from same seller, this has a higher likelihood to be DD?

This was the one I got, AT88-S1: https://www.ebay.com/itm/222716613498

That is the almost the same drive as mine, but the add-on card is larger with more chips. This is likely the double density card rather than just a data separator like mine.


The end of the PCB sticking out the back left is for connecting slave drives, there are jumpers to configure and the terminator chip would have to be removed. This Percom drive doesn't have a printer port.


A manual is available on Atarimania. http://www.atarimani...rive_manual.pdf





On the AT88-A1 slave mechanism the card edge for the ribbon cable appears to be sticking out between the side and back panels, to the left of the fuse holder.

In Topic: What's the latest Atari related thing(s) you've bought on ebay?

Mon Dec 11, 2017 3:41 AM

Will do! I'll start a separate thread when I do. It has other oddities too like formatting DD disks with a skew that's not actually optimal for itself, and non-zeroed sectors. Hopefully I can dump any ROMs on it eventually. It's labeled an AT88-A1.

Are you certain it's an AT88-A1. The FAQ on Atarimania lists that as a slave mechanism, which is meant to be connected to another Percom drive with controller. 



I have an AT88-S1 I got about 5 years ago which is only capable of single density. It does have a small PCB plugged into the socket for U6 which I'm fairly certain is a data separator upgrade. 

In Topic: Atari 1010 only plays one channel

Tue Dec 5, 2017 10:33 PM

The issue could also be with the computer or SIO cable. The tape audio is on pin 11 of the SIO(AUDIO IN), and is then mixed with POKEY audio.

In Topic: Expanding the 400

Tue Dec 5, 2017 10:20 PM

Mistake was on the ram board. So now I guess I need to go back through again and see if I can find any reason at all for a black screen. I noticed that your original instructions say to use 4164 ram chips, do the 4564's I used work? They seemed to be fine @ 16k level. 

Part #s for the 64k x 1bit DRAM chips can change depending on the manufacturer, 4564 is the # Mostek used.

In Topic: Best 8-bit Atari disk drive? 810, 1050, XF551

Mon Dec 4, 2017 11:48 PM

Even the ST/TT computers were only 720k until they used hand selected / tested WD1772 chips in order to be HD capable, when Atari couldn't obtain these any more they developed the AJAX FDC.