Rowe Ami memory unit 301-07855 schematics needed.

omegaman

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I just picked an R-81 up, dead on arrival. I decided to open up each module to see what was up. The memory unit had battery acid all over it :( I've cleaned it up and removed the corroded components. My manual only has the schematics for the 601-07666 pcb where as mine is 601-08584 pcb. I need to know what transistor are used for :
Q701, 702, 703, 704, 705, 706 and q708.

Thanks
 
Hello,

If you get stuck with the repair then I am in the UK, I repair these boards but require the following to test as a set of boards:

Memory Unit
Mechanism Control
Selector Logic.

Regards
Alan Hood (ami-man)
Games Unlimited & Datex Systems
Units 4 & 5 Lion Park
New Street
Halfway
Sheffield
S20 3GH

0114 247 0242 phone
0114 251 0727 fax
[email protected]
 
Thanks for the offer Alan.

There seems to be little info for in depth repair of the electronics for these machines.

I really should have bought a new memory unit but I hate giving up on repairing stuff like this.

In the end I had to repair broken traces, reflow all the header pins, replace the 24 pin IC socket, fit a new timing capacitor and sync it with the Logic selector timing, replace 7 corroded transistors and fix the power supply.

I was very happy when I fired it up....its rough around the edge but will be fun for the kids to play with.

http://www.youtube.com/watch?v=UE2CnytLVpo
 
Hello,

Glad to hear that you have got the R-81 sorted, if you require any of the nylon gears or other parts for the 1100/12 mechanism I have them in stock.

That varible cap was always an issue, you use it to alter the clock/data pulses.
The MPSA06 & MPSA56 are used on most of the other Rowe Ami boards.

Regards
Alan Hood
ami-man
UK
 
Hi Alan

Bit of an update on this, I was getting decent data send pulse on my scope at pin 3 of IC z704, I was getting corrupt data receive pulse on pin 22 of z704.....Both the clock, data and -17v LED's on the memory unit were shot. I think one was dragging down the data signals.
I replaced them and now they flash properly and the machine works perfectly.

I set the frequency of the cap at 48 KHz on both the memory and logic units...is it critical for them to be exact? seems to work fine.

The only problem now to sort is the record return arm gets jammed when returning a B side only.

Do you have a motor in stock? The seller said he would send me one but its not here yet.

Thanks
 
Hello,

If you have a R-81 manual go to page 2-60 and check out the Sector gear adjustments.
The main issue will be that the roll pin not adjusted correctly and is allowing the Toggle Linkage to move back thus allowing the toggles to move. It's only the toggles being in the correct position that flips the gripper bow upright.

I would also check out all the other adjustments relating to the transfer i.e. tone arm cam, cam & trunnion drive gear etc.

Regards
Alan

Alan Hood
ami-man
UK
 
Having a bit of trouble with this again. Now when powered on the records keep spinning and don't stop. 200 to 299 displays correctly over and over and the record playing lamp is lit. I can add a credit and make a selection but it makes no difference. If I hit reset on the memory unit the records stop spinning but when I let go it carries on. Data and clock lights are flashing.
I think the memory unit is the problem.
 
@omegaman,
I hope you're still checking in from time to time. I picked up non-working R-82.

This is my latest observation. These selections were made in secession one after the other after each record had been returned and magazine returned to home position. It seems to show a warmup of circuitry.
Selection 101 picks up Slot 9 rather than Slot 1, next time Slot 6, then 2, & 2 and then 1, 1, 1. I then selected 102-106 and it picked them correctly. Then I selected a B side, and I heard a click (B side solenoid) and the display stopped on the correct number, but the magazine continued to spin without end and the data LED had stopped flickering and was out. I cycled the power at the Scan Control Console and when it came to rest, I reset the Memory Unit. The data LED is lit, doing its flickering but now misses every point selected and will no longer pick up any records. Sounds like something was not only warming up but failing and the Mech. Control isn't receiving any signals. I checked all the transistors and diodes in the Memory Unit. Maybe a weak cap or resistor changed value while being loaded? I would just replace all six of the fixed capacitors, but I imagine four of them would have an effect on the trimmer cap circuit.

I see you set the frequency of the trimmer cap at 48 KHz on both the Memory Unit and Selector Logic unit. On the Memory Unit are you measuring the frequency right at chip Z704 Pin #7, Clock Send and (chassis as ground) also at Clock Send Pin#25 at Selector Logic chip Z501?

Thanks for any help that can be offered. These boards were worked on by someone who offered to help the previous owner. They were still in the shipping post box from 2022. Whatever work was bought and paid for didn't last the test of time in the box from the UK.

Thanks, - Tom
 
@omegaman,
I hope you're still checking in from time to time. I picked up non-working R-82.

This is my latest observation. These selections were made in secession one after the other after each record had been returned and magazine returned to home position. It seems to show a warmup of circuitry.
Selection 101 picks up Slot 9 rather than Slot 1, next time Slot 6, then 2, & 2 and then 1, 1, 1. I then selected 102-106 and it picked them correctly. Then I selected a B side, and I heard a click (B side solenoid) and the display stopped on the correct number, but the magazine continued to spin without end and the data LED had stopped flickering and was out. I cycled the power at the Scan Control Console and when it came to rest, I reset the Memory Unit. The data LED is lit, doing its flickering but now misses every point selected and will no longer pick up any records. Sounds like something was not only warming up but failing and the Mech. Control isn't receiving any signals. I checked all the transistors and diodes in the Memory Unit. Maybe a weak cap or resistor changed value while being loaded? I would just replace all six of the fixed capacitors, but I imagine four of them would have an effect on the trimmer cap circuit.

I see you set the frequency of the trimmer cap at 48 KHz on both the Memory Unit and Selector Logic unit. On the Memory Unit are you measuring the frequency right at chip Z704 Pin #7, Clock Send and (chassis as ground) also at Clock Send Pin#25 at Selector Logic chip Z501?

Thanks for any help that can be offered. These boards were worked on by someone who offered to help the previous owner. They were still in the shipping post box from 2022. Whatever work was bought and paid for didn't last the test of time in the box from the UK.

Thanks, - Tom
As long as April of 2024 meets your definition of "from time to time."

I wouldn't hold my breath if I were you.
 
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