Algie

No Switches. The 25pin connector is the confusing bit. There is one link to the PIA aswell (pin 21).

I have just bought an 800xl from ebay because I noticed an extra LED on the case top. Sure enough there is an upgrade within. Can anyone identify it? Pictures of the board are below. A 25pin D socket has been added to the back with connections to pins 14 to 19 so not a serial interface? Maybe a MIDI? There is a header cable into socket U3 and the board sits in U2. Algie

Something like this? Except I don't have an LED for the Write protect switch, it's just labeled overdrive and normal. It says, "Override". Maybe you should paint some go faster stripes on it :0)

PAL machines, are you in the UK? Maplin do a conductive paint pen. A bit pricey though - 21.00 GBP Also, I have a spare Keyboard. Algie

Found another instance here: http://mega-hz.no-ip.com/ATARI/alte gesicherte ATARI Seiten/atarimods/www.geocities.com/atarimods/index.html Algie

I found these images that are for 27C32 EPROMs. They are probably for the KPI interface and my guess or hope is that the KPHD12 file is the original EPROM with 2 partions on a 20Meg drive. Maybe somebody else will know. Hope this helps. Algie KPHD12.bin KPHDMOD1.bin

Just for interest, I have done a parts search on Jameco and my estimated cost is spot on. A lot less fuss than searching through UK sites and hoping you find stuff so I may order from them if I end up building several. So the U.S. of A. cost will be $35 inc P, P & P (Postage, packing and a pint for my trouble). Algie Sounds fairly easy I'm in the US so the exchange rate might make it a little more than I might want to pay, but I'll wait and see Thanks for your info...

You live and learn. I have not had problems formating to enhanced density and there is no double density available with the switch in native postion. That's the advantage of the switch. With a HAPPY drive you have to run software to make it UNHAPPY but the LAZER has a switch. 10 Minute later.... I have just tried Transdisk IV with a LAZER in 1050 mode and it formats to 1050 Enhanced automatically. In HAPPY or USD modes you get double density. Did not find a single density option. I may have the Quad OS you mention or I could make one. I have a couple of Quad chips but I have forgotten which 4 OSs are on them. I have images of the most upgrade OSs but no instructions Algie

I am going to base the cost on how much it will cost to replace the bits from cheap online sources and recycling and then you buy me a pint. On a good day I can find the bits for about £12 so lets say £17 including P,P&P (Postage, packing & Pint) Fitting is very akin to the US Doubler plus you drill a small whole for the switch. I will include full instructions.

The ROM contains all 3 operating systems and you select with the switch before turning on the drive. This is a lot easier than running software to make the drive UNHAPPY (Some software will refuse to run if it detects these drives so you just flick the switch to 1050 native or USD mode). The install is about as complex as a US Doubler upgrade. You need to open the drive, remove the metal screening and then replace 2 of the onboard chips with the upgrade. The chips are socketed so you will not need to solder these. You may have to move 2 wire jumpers on the circuit board which are soldered but that is it. Atari produced 2 different ROMs with slightly different pinouts. If the jumpers are in the wrong position you will lose native 1050 mode until you move them. LAZER and USD will still function. Lastly you will need to drill a small hole in the front face for the switch. If you are in UK I could install it for you... Algie

If you still have the old Lazer it may be repairable. Could also send you replacement ROM and Processor to get back to a standard 1050. Other goodies found in the loft were; various pulled Atari chips, my Eprom burner and a couple of SpartaDos disks covered in ROM images for things like Omnimon XL, Ultimon, and Cupid. Also a lot of original disk software which is now safely away from the frost. Count me in! I have a Lazer from way back when but it stopped working a year or two ago. Swapped in several working drive mechs but to no avail. I think it might be the firmware. Another Lazer would be great and also help confirm the prognosis of the original... Any other goodies stashed away in the loft?!

Hi Carmel, Nice to hear from you. I am in the East End now. I have a couple of spare 1050's. They will be getting upgrades and on evil bay soon. Algie

Went rooting through the loft and found some homebrew LAZER/USD 1050 drive upgrades. Also found a lot of the necessary chips to build more. If I put a few of these together is anybody interested? They provide 3 modes of operation via the switch; Happy, US Doubler or ordinary 1050. I may also do some reconditioned drives with them ready fitted. I am UK based but the chips should post worldwide cheaply. Algie

I did several 65XE to 320XE upgrades. The only difference is the custom IC. I bought 1/2 a dozen of these from Best at a computer show at Wembley when Brad used to visit the UK. Cleaning out the empty memory bank of solder on the motherboard is the main pig with these. A mate gave me a desolder station with an electric pump eventually, bless him. The price is probably related to how often these get requested and earning a crust more than pure material cost. I have no idea if the kits include socket or desolder wick.... Algie

I have just started moding my XL/XE comps again for fun. I am finding that I have to dig quite deep for some of the bits as the electronics hobby as all but gone. I also noticed that a number of people are preparing to upgrade so I was wondering if we should pool our resources. I would be interested in swapping chips or even putting upgrade kits together. I have just found 7 Laser drive EPROMs amongst other Atari related ICs. If only I could remember what to do with them :0) Thoughts, Algie