Paul Westphal Posted March 13, 2014 Share Posted March 13, 2014 I recently got two 810's. One works and the other doesn't. The one that works has a board on top - Is this a happy 810? Quote Link to comment Share on other sites More sharing options...
Bryan Posted March 13, 2014 Share Posted March 13, 2014 No, it's a revision update. The 810 originally had the analog circuitry on the power supply board. Quote Link to comment Share on other sites More sharing options...
Marius Posted March 13, 2014 Share Posted March 13, 2014 A clue is the original Atari logo on the PCB. A happy is a third party upgrade. Does the happy 810 also have a 6502? Quote Link to comment Share on other sites More sharing options...
Bryan Posted March 13, 2014 Share Posted March 13, 2014 I believe the Happy 810 was just a hack to add more RAM and a new ROM. I don't think it added a new CPU. Quote Link to comment Share on other sites More sharing options...
BillC Posted March 13, 2014 Share Posted March 13, 2014 I recently got two 810's. One works and the other doesn't. The one that works has a board on top - Is this a happy 810? According to the BEST Electronics website the original power supply board, which is in the one without the analog board on the drive mechanism, has a 100% failure rate. This means that is most likely the problem with the dead drive. As both these drives appear to have the Tandon mechanism you may wish to check it the drive doors have been replaced, and also what Revision ROM(C being the last) they have before you place an order. From the Best website: Atari Engineering Grass Valley 810 Analog Rear board upgrade set. New Rear 810 Analog Rear Power board, New Top Analog R/W board, New 10 Pin Jumper cable, Installation Instructions. Upgrades / Replaces the older Atari 810's with Single Power board that 100% Fails. See Atari 810 Tec tip below! CB101128 $35.00 Atari 810 Tandon New Upgraded / improved front lift door. Cures the known problem with old Atari 810 Tandon doors with white pivot pins that break close to 100% of the time. FA100467 $4.95 CO11299 (810) Rev C $5.00 1 Quote Link to comment Share on other sites More sharing options...
ACML Posted March 14, 2014 Share Posted March 14, 2014 I too have had both. The one without the top Grass Valley board set did not work either. The ones "without" are early 810's, but don't dump them as the MPI mechanism is probably "like new". Since they failed quickly, PCB's that is, those "without top board" 810's probably got put back in the box and were never to be used again. That means the MPI mechs have seen little use and can be swapped out on a good working 810 to make it like new again. Also, the plastic cases are probably un-yellowed because they were put away and not soaking up UV light for 30 years. I used the mech and plastic from one of these "without top board" 810's to fix two other functional, but needing new part 810's (i.e. hold onto it for parts or get the Grass Valley board set). Quote Link to comment Share on other sites More sharing options...
atari8warez Posted March 14, 2014 Share Posted March 14, 2014 A clue is the original Atari logo on the PCB. A happy is a third party upgrade. Does the happy 810 also have a 6502? Keen eyes Quote Link to comment Share on other sites More sharing options...
Paul Westphal Posted March 16, 2014 Author Share Posted March 16, 2014 I'm going to keep it and get the new boards for it from Best for $35.00 plus ship. The case is fine and the internal's look like new. This will be my first 810 rebuild. Quote Link to comment Share on other sites More sharing options...
BillC Posted March 16, 2014 Share Posted March 16, 2014 I'm going to keep it and get the new boards for it from Best for $35.00 plus ship. The case is fine and the internal's look like new. This will be my first 810 rebuild. You could try swapping the power/analog boards into it from the good 810 first, if it works this would verify that is the only problem. Quote Link to comment Share on other sites More sharing options...
Paul Westphal Posted March 16, 2014 Author Share Posted March 16, 2014 Will do Bill. That will get me familiar with disk drives. I have fixed 400/800's, but never a dd. Quote Link to comment Share on other sites More sharing options...
tschak909 Posted March 18, 2014 Share Posted March 18, 2014 How many 810s with Tandon mechs were manufactured, versus the MPI mechs? I've only had the MPI mechs. -Thom Quote Link to comment Share on other sites More sharing options...
ACML Posted March 19, 2014 Share Posted March 19, 2014 (edited) How many 810s with Tandon mechs were manufactured, versus the MPI mechs? I've only had the MPI mechs. -Thom tschak909, Good question. I can tell that the Tandon mech was "bill of materials" by June 1983. When you look at Ebay, +90% are MPI mechs. I think that percentage is not an accurate indication of the ratio though. The Tandon mech 810's all suffer the fatal (white teflon pin) failure that makes the door fall off in your hand. I think sadly that many Tandon mech 810's found their way to landfills because a fix in the late 80's and 90's was not common. I've also heard that Tandom mechs lose alignment more easily. I'm curious myself about the production ratio. Anyone know? Edited March 19, 2014 by ACML Quote Link to comment Share on other sites More sharing options...
svenski Posted August 8, 2020 Share Posted August 8, 2020 Does anyone know if you can source the Tandon mech door improvement from anywhere other than Best? I'm guessing shipping would be a pain. I'm just going looking at two 810s. The first does not have the analog board but has an MPI mechanism (garage door?), the second has the analog board, but has the Tandon mechanism. There seems to be one brass pin in the door latch and nothing at the front of said latch. The latch is loose and whilst it can close, it goes too far so the drive mechanism opens up again. I'm yet to try with a disk to see if that will stop this happening but the latch doesn't look right. Or, can you source replacement pins? Has anyone 3D printed these? The non analog drive is powering on and making all the right noises so I'm going to tinker with that a bit. Quote Link to comment Share on other sites More sharing options...
svenski Posted August 8, 2020 Share Posted August 8, 2020 So a quick update; first drive which has some cosmetic damage and doesn't have the analog board is working but slow. Seems to get better after being run a bit - a bit like a car coming out of lockdown. I'm going to try and adjust the speed. The second drive with the one-pin door is loading fine however, with the door as it is, the mechanism won't stay down so I had to improvise to do a test. Quote Link to comment Share on other sites More sharing options...
+Nezgar Posted August 13, 2020 Share Posted August 13, 2020 On 8/8/2020 at 12:04 PM, svenski said: Does anyone know if you can source the Tandon mech door improvement from anywhere other than Best? I'm guessing shipping would be a pain. Shipping will the least of your concerns if you are in the USA. The issues are usually that he has a minimum value order, and Best also restricts most people to 4 or 5 items per order. International shipping can be expensive. Brad does have a lot written up on the website about the problems with earlier 810's without the "Grass Valley" upgraded board set, and the later tandon's with the broken door pin. He sells both sets of parts, but not very cheap. On 8/8/2020 at 12:04 PM, svenski said: The non analog drive is powering on and making all the right noises so I'm going to tinker with that a bit. The original power board has an extremely sensitive RPM dial. moving it a mere millimeter either direction can result in a + or - 10RPM variance, if it even lets you get up to 288RPM at all. It has inferior power output compared to the upgraded "Grass Valley" board set drives. Start an RPM test, ie using the one that comes on some SpartaDOS 3.2 disks to check that. Earlier 810's used MPI mechs. Later used Tandon. The MPI drives started with inferior power boards and no data separator daughterboard. The "Grass Valley upgrade" consisted of replacing the rear power board with an upgraded power board + separate top analog board, added a data separator between the WDC controller on the side board, and replaced the older "Rev B" ROM with a "Rev C" ROM that formatted disks with an improved sector interleave. Quote Link to comment Share on other sites More sharing options...
burkhart87 Posted February 26, 2023 Share Posted February 26, 2023 On 8/8/2020 at 2:04 PM, svenski said: Does anyone know if you can source the Tandon mech door improvement from anywhere other than Best? I'm guessing shipping would be a pain. Or, can you source replacement pins? Has anyone 3D printed these? I used these: https://www.ebay.com/itm/165893137075 Quote Link to comment Share on other sites More sharing options...
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