xf551 CSS XFD 1.5 Dual drive XF551 trouble shooting

[jcbstein]

Need help getting an Atari XF551 drive working that has the XFD 1.5 ROM for dual drives.

I recently acquired a dual drive XF551 that does not work properly.

When I opened up the drive, I noticed the positioning of the ROM in the socket is to the back 24 pins of the 28 pin socket. Should the chip start at the notched end of the socket? (see picture)  I can’t seem to find a how to install manual for this.

When I tested the5.25” drive from the dual drive unit on another XF551, the drive light would come on, and the motor would spin, but the read/write head did not move.

When I tested a known working drive on the XF551 with the XFD ROM the drive did not work, so I have to resolve the issue with the circuit board in that drive as well.

There is also another module attached that I don’t know what it is for. (see pictures)

Any help is appreciated.

 

[sup8pdct]

What you have is the CSS duel drive upgrade. excellent bit of gear. it adds USD like features to the XF551 and makes the drive an overall much better unit. Don't know why you would want to change it.

 

The rom is correct. The XF551 comes with an 8K rom from factory but the controller chip (8040 or 8050) can only access 4K in 2 X 2K banks.

1/2 of the rom isn't used. The socket is setup so the smaller rom will work.

 

The module is required to select between the 2 mechs. If you look at each mech, the 5.25 is jumpered as 2 and the 3.5 as 3.

If you want to test those mechs in another xf551 drive, you will need to set the jumper back to 1. Also plug the card edge connector in correctly into that small adapter with the 2 black wires soldered to it. you will see the 1 of the conductors is cut off and the cable moved over 1 position. Tose connectors were never designed to go back to back, so the longer ribbon cable has been adapted to work.

 

As for why it doesn't work, it is hard to say. Those main boards are rather cheap and do tend to break the solder joints around the power plug and sio connectors. Also heard about the ribbon cable connector on the motherboard giving problems. Check voltages

 

Reminds me of a poor lady once who had an xf551 and a Atari daisy wheel printer and was writing a book. After some time, the drive failed to respond. she noted the printer didn't work when plugged into the drive, but did work when plugged into the computer directly. She concluded that there is a problem with the drive. With nowhere else to go, she rang Atari Australia and sent the drive to them. Atari came back and said there wasn't a problem with the drive, the problem has to be with the computer and then tried to sell her an ST. After more digging, she eventually found me VIA local Atari club and told me her story. As the drive wasn't returned yet, i tested her computer and found it worked perfectly.

Following weekend, she came back with drive in hand which i immediately plugged in and found a problem with the power plug, It was very sloppy and wouldn't power on. Upon looking on the under side of the board, the power socket had massive holes around it and most solders on each sio connector were broken. Took a bit to repair and also fixed the sio connectors to the board as there were none. Gave her a better Dos and sent her on her way.

Makes you wounder what was going on at Atari Australia.

 

James

[jcbstein]

I pulled the controller board out  to inspect it and here are some pictures. I am guessing who ever installed the upgrade did some solder work to resolve the bad connection issue. In the close up picture, there appears to be a break in the trace right next to the power plug though, if I am looking at it correctly.

Edited March 11, 2022 by jcbstein

[Mathy]

Hello jcbstein

 

Maybe this is of some help.

 

Sincerely

 

Mathy

 

[sup8pdct]

I think that has something to do with the dc socket used. It may have shorted inner and outer with that trace so it has been cut.

 

The other wires are due to the SIO connectors not fixed to the board and only relying on the pins and the single sided board to take all the strain to insert/remove the SIO cable. Damaged tracks and broken solder joints is what happens. If possible, fix those connectors down with screws going in to the plastic going up, similar to the ones holding the circuit board down or small bolts and nuts.

 

It looks like a couple of those solder joints on the SIO connectors are cracked. Maybe best to re solder them just to be sure.

 

James

[cwilbar]

8 hours ago, sup8pdct said:

I think that has something to do with the dc socket used. It may have shorted inner and outer with that trace so it has been cut.

 

The other wires are due to the SIO connectors not fixed to the board and only relying on the pins and the single sided board to take all the strain to insert/remove the SIO cable. Damaged tracks and broken solder joints is what happens. If possible, fix those connectors down with screws going in to the plastic going up, similar to the ones holding the circuit board down or small bolts and nuts.

 

It looks like a couple of those solder joints on the SIO connectors are cracked. Maybe best to re solder them just to be sure.

 

James

Another member here made a PCB you install on 'top' of the protruding pins/etc and solder to effect repairs.  I can't recall which member it is now.

 

Never understand why Atari chose to use Yak spit to hold the copper on the PCBs ? .....  I'm pretty good at soldering on old stuff, and the XF551 is always a challenge.

 

Who knows, in another 10 years, maybe the traces will be falling off the PCBs.

 

All in the name of saving $0.001 per unit.

 

 

[manterola]

Yes, it is my design. Not perfect yet, but quite useful.

I gave away all the PCBs I had, but I will share the design with the community, soon.

[jcbstein]

Well, after some testing, the 5.25" drive mechanism works flawlessly when tested on my other XF551.

 

I tested the SIO contacts from SIO 1 to SIO 2 and I have continuity on all pins.

 

Now I just need to resolve the power issues.

 

[jcbstein]

19 hours ago, Mathy said:

Hello jcbstein

 

Maybe this is of some help.

 

Sincerely

 

Mathy

 

Thanks, it got me on the right track. (pun intended).

 

[+kheller2]

bump - some pics!

 

[sup8pdct]

Am looking but don't see any pics
🤔