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AMI R-81 Memory Unit
On Apr 2, 9:11*am, (James McClave) wrote:
When you make a selection , it just scans past it and wont select any record. Memory unit is bad , had it tested by the guy in new england , The micro processor chip is bad. Jim Sounds like it, its just that one problem we had frequently many years ago (where the numbers on the display werent counting in proper sequence sometimes as the magazine scanned, and the magazine might scan constantly) could be cured by adding 9 x 10k 1/4 w resistors from the encoder wheel signal lines (9 of them - one resistor per signal line) where they entered the chip, to the -17v rail. Please use anti-static procedures (earthed wrist strap, earthed soldering iron tip, earthed anti-static mat etc) if you decide to try this. I have had a third machine come in today from a person who has it in home use with one of these "memory units" dead today. I'm starting to warm more and more to the feasibility of designing a modern micro controller based substitute, otherwise a lot of these machines will be scrapped. (unless someone out there has already designed a replacement board) Even if there was a supply of NOS chips around, the expense of them, and high failure rates they have means that there is a high risk of you spending a lot of $$ to only have the same problem happen again in the future. E-mail us at: If you dont care about keeping the machine original internally - (ie: playing actual records) then consider one of these MP3 conversion kits that are designed EXACTLY to retrofit record mechs, and make the juke look and work normal from the outside. http://www.cdadapter.com/jcu.htm you would have to: -Do small modifications to the display and keyboard circuit boards -Make a wiring harness to suit and provide a 13v power pack for the replacement board -Rip your records into MP3 and load them onto the CF or Hard drive. The advantages are Ability to load any song you want in there - even if not released on vinyl Not have to buy expensive 45's, range is probably very limited by now not have to replace needles, repair mechanism, or worry about memory unit problems Replace unused "b" sides with other songs that you will play. |
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AMI R-81 Memory Unit
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#13
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AMI R-81 Memory Unit
On Apr 5, 11:14*am, (James McClave) wrote:
Wow , lots of good info there. The resistor idea sounds kind of tedious. Give it a go, you have absolutely nothing to lose, if the chip is indeed stuffed. Whenever you get random counts, numbers missing etc, this is always the cause. The memory unit cant find the "77" or "27" numbers, or detects the number sequence problem, and keeps searching. As this device isnt particularly intelligent, it has no "time out" etc and just turns forever. Its from the wipers making bad electrical contact with the disc, they can connect and disconnect as the disc turns (its probably warped very slightly or something) I would not advise doing anything at all to the disc as it is gold plated, The resistors fix it by providing more current through the wipers (note this is now standard practice in ANY design involving an IC and a mechanical switch) making sure they will conduct and send the right signals to the IC Not crazy about the MP3 idea either. Yes, the numbers when scanning did not read in sequence either. Too bad, from what I know this memory unit was only used in this model and maybe the R-82? * Jim E-mail us at: Was used in everything ROWE made in solid state prior to R-84 I personally have seen this system in RI-1, R81, R82, R83 I think that the 1975,6 models were available as either solid state (with memory unit) or electro-mechanical. I have no idea how many were sold in each type or how popular they were. There are few US made solid state ROWE here in Australia prior to R-81. Last week I copped a service call from a private owner to service a "ROWE electronic" that was in a woodgrain cabinet with a lift up lid. I thought originally it was a kentwood (1979 with central control computer) and that it would be a simple repair, but to my despair it had the old board set, and a totally dead memory unit, scanned indefinitely and showed nothing on the display - (except when you punched in a selection). With the cost of an exchange unit, and 2 way international postage approaching the best part of $400 AU he still seemed keen to get it fixed for some reason, and didn't want to go with the MP3 option. Had one R-83 machine come in this week for repair. After I fixed other faults in the unit, it turned out that it had a "sort of" working memory unit, however it repeatedly plays "293" over and over indefinitely after playing the selections that you DO want (until you hit the "clear memory" button.) While we had the chance (with a working memory unit in captivity), we took it apart, monitored the serial interface, drew up timing diagrams for the serial interface, and the sequence of operation of the IC and feel more confident now about it being feasible to make a substitute, since there seems to be enough demand (and dead machines piling up, taking up room in my workshop). Once I get a few jobs out of the way, might start on a prototype |
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AMI R-81 Memory Unit
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AMI R-81 Memory Unit
On Monday, March 23, 2009 at 10:04:20 PM UTC-4, James McClave wrote:
Still looking for one of these. If anyone has a good one, give me a holler. Thanks. E-mail us at: Hello, I am with a doubt. My uncle over seas has one of this unit. It broke and a tech when to fix it. He said that he could not repair the part in there and took it with him. He was never seen again. He is missing the module ( board ) that goes under the Memorec Selection Computer. There are two or three connectors. I have a couple of pictures if that would help. Does any one has any idea of what part goes in there and if there is any hope in getting that part. I would appreciate any help on this. Best regards, Ed. |
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AMI R-81 Memory Unit
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#17
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AMI R-81 Memory Unit
On Sunday, May 1, 2016 at 6:45:41 PM UTC-4, wrote:
On Monday, March 23, 2009 at 10:04:20 PM UTC-4, James McClave wrote: Still looking for one of these. If anyone has a good one, give me a holler. Thanks. E-mail us at: Hello, I am with a doubt. My uncle over seas has one of this unit. It broke and a tech when to fix it. He said that he could not repair the part in there and took it with him. He was never seen again. He is missing the module ( board ) that goes under the Memorec Selection Computer. There are two or three connectors. I have a couple of pictures if that would help. Does any one has any idea of what part goes in there and if there is any hope in getting that part. I would appreciate any help on this. Best regards, Ed. It sounds like you may be talking about the " Selector Logic Module " and if not that the " Memorec " popularity meter circuit board. If it is the popularity meter module, your machine should be able to play without it. For the interest of others and to answere what I have read in other posts associated with this thread: The first generation AMI Electronic Operating System was used in models R80SS up thru R83. It was introduced part way thru the production year of R80 which still employed the electromechanical system ( search unit etc. ) It was designed to make the change from mechanical to electronic as easy and well laid out as possible such as the Mech. Control module put in the same place as the former Mech Control Relay. The encoder and memory unit put in the place that formerly had the search unit. Credit computer on the rear wall similar to where the electro mechanincal credit unit was etc. There was an earlier electronic credit unit used in the R-74 but as I recall only used in one or two model years. AMI's first all electronic control system as used in Models R80SS thru R-83 had few problems, was quite reliable for the expected commercial life of the Jukebox which is about 10 to 15 years. There were a few problems with the custom chip used in the memory module. Sometimes it would only affect the digital display but otherwise the machine would work ok. Some of them as described in this thread wh en they went bad rendered the machine totally unusable. AMI Models R-82 and R-83 were a big hit with operators because it was the first cabinet design in many years with no flat surfaces where location patrons could put drinks on it, use it as a table or sit on the program glass. Unfortunately if liquids were spilled on the top of the machine some of it would leak through the hinge. At one time, quite a few years ago now, I think someone came up with a replacement for the custom chip used in the memory module but I can not recall who it was. Might have been someone in Texas but that is all I can remember. I still have an R-83 that I bought many years ago, still working ( home private use ) and knowing about the custom chip I bought some extra modules as they were being retired from commercial service. Sorry, at this time I am not selling any of my spares. You might try durfee coin op I think his website might be www.jukeboxparts.com. He might have some modules parted out of machines. There were two types of memory modules for this system. The earlier one had a separate battery and charger module. The later version which also included " autoplay " should be directly replaceable, had the battery unit built into it. These were great sounding machines when they are in good working condition. |
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