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Thread: Finally started

  1. #1
    Join Date
    May 2018
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    Lancashire
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    Default Finally started

    I got my model 4 from work sometime back but its been awaiting bench space.

    Now the Apple is working, strip down and inspection has begun.

    20190521_164734.jpg

    As I lost track of this machine for 25 years before finding it in a locked store room, its picked up a bit of light corrosion and both disk drive spindles were stuck, so drives out for a strip down. Head drive feels 'ok' and dont want to loose alignment, but might have to do these bearings too.

    20190521_164742.jpg

    (shot on top of one of the new VAX's )

    PSU first. Want to power it up without the system connected but first job is to replace the RIFA's

    20190521_164723.jpg

    Why did they think it was a good idea to attach the tube to the upper case !, accident waiting to happen.

    PCB looks ok

    20190521_165546.jpg

  2. #2
    Join Date
    Mar 2016
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    Pikesville, Maryland
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    Default

    From your photo of the motherboard --- the wire coming of C39 indicates this is a 64k machine. You can up to 128k by adding 8 x 6164 ram and "moving" the wire from C39 to PIN 16 on U33 (chip just left to C39). BE CAREFUL - use small tipped soldering iron if possible

    Where else could they have located the monitor in the all in one system? With care and following the simple method for removing the case I have yet to crack a CRT tube (and I have done quite a few). As you lift the case --- look thru the drive bay and watch the tube neck as you lift the case so that you do not get tangled up in any wires/harnesses. I think RS could have made it easier by making sure the "path" of the tube neck was completely clear of any obstructions so that lifting up the case would have no issues. When I refurbish a unit I make sure all cables are out of the way of the "path" of the neck of CRT to avoid future problems

  3. #3
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    Lancashire
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    Default

    Cheers, yep its a 64K machine. The CEGB spared no expense. It was used as a development machine for a Z80 based custom ethernet communications device (that are still going !)

    As to placement of the CRT, I think I would have mounted it and the board in a frame connected to the lower case half, so that lifting the top would leave it in place. Its not like they were cutting corners in construction, its fairly beefy elsewhere

    Do you think I should replace any other caps apart from the three RIFA before powering on, given that its been powered down since about 1990 ?

  4. #4
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    May 2018
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    Lancashire
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    Default

    Hum

    Disk drive main spindle a bit stiff, easy to tap out

    20190522_113648.jpg

    and give the bearings a good clean, really they should be replaced but will do for now.

    20190522_113828.jpg

    Disk drive motor bearings also partially seized.

    Easy strip down... Not.

    Didnt expect it to be a brushed DC motor, brushes popped out, luckily one stayed in the motor body and one I found on the floor, need to remember its 30 years old !

    So all the bits and bearings cleaned and spinning nicely, but its going to be a nightmare to replace the bushes. Got a pinion puller on order so hopefully can get the pulley off the shaft and re-assemble the top bearing and brush prior to replacing back in the body.

    20190522_123504.jpg
    Last edited by Gary C; May 22nd, 2019 at 04:44 AM.

  5. #5
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    Default

    RIFA's replaced and PSU energised, volts all good.

    and it lives !

    20190522_174717.jpg

    Almost forgot how beautiful a CRT tube is.

    20190522_175139.jpg

    Disk drive spins up, but used a slight amount of lubricant on the bearings so want to give it a good while to gas off, then give it a further clean before putting a disk in it.

    Why does it ask cassette ? then want to know memory size, is that an indication something isnt working ?

  6. #6
    Join Date
    Apr 2018
    Location
    Los Angeles, CA
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    Default

    Quote Originally Posted by Gary C View Post
    RIFA's replaced and PSU energised, volts all good.

    and it lives !

    20190522_174717.jpg

    Almost forgot how beautiful a CRT tube is.

    20190522_175139.jpg

    Disk drive spins up, but used a slight amount of lubricant on the bearings so want to give it a good while to gas off, then give it a further clean before putting a disk in it.

    Why does it ask cassette ? then want to know memory size, is that an indication something isnt working ?
    it usually only asks that if it's not detecting the drive. Maybe double check you connected them back up properly? the drive light should come on when you turn on the system.
    -- Brian

    Systems: Amstad PCW 8256, Apple IIe/II+/Mac+/Mac 512k, Atari 800/520STFM, Commodore 64/Amiga 3000/PET 4032/SX-64, IBM PS/1 2121-B82, Kaypro II, Osborne 1, Tandy 1000 SX, TI-99/4A, TRS-80 Model 4 GA

  7. #7

    Default

    I have LOTS of experience with "Cass?" recently. Like ngtwolf said it's usually a bad drive, you can try each drive alone and see if it works. When it's working you should see "Diskette?" when you turn on the computer with the drive door open. For me it was a bad floppy controller behind the non-gate array motherboard. It could also be a bad cable: between disk drives and motherboard, or the flimsy cable between motherboard and floppy controller.

  8. #8
    Join Date
    Mar 2016
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    Pikesville, Maryland
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    Default

    Quote Originally Posted by Gary C View Post
    Cheers, yep its a 64K machine. The CEGB spared no expense. It was used as a development machine for a Z80 based custom ethernet communications device (that are still going !)

    As to placement of the CRT, I think I would have mounted it and the board in a frame connected to the lower case half, so that lifting the top would leave it in place. Its not like they were cutting corners in construction, its fairly beefy elsewhere

    Do you think I should replace any other caps apart from the three RIFA before powering on, given that its been powered down since about 1990 ?
    Thats the only ones I've replaced ---- all the others seem to be in good condition for their age ---- but if you have the time, energy and finances then go for it

  9. #9
    Join Date
    Mar 2016
    Location
    Pikesville, Maryland
    Posts
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    Default

    Quote Originally Posted by Gary C View Post
    RIFA's replaced and PSU energised, volts all good.

    and it lives !

    20190522_174717.jpg

    Almost forgot how beautiful a CRT tube is.

    20190522_175139.jpg

    Disk drive spins up, but used a slight amount of lubricant on the bearings so want to give it a good while to gas off, then give it a further clean before putting a disk in it.

    Why does it ask cassette ? then want to know memory size, is that an indication something isnt working ?

    You should only see this if either (1) power up the system while holding the BREAK key or (2) no FDD daughter card installed or defective card, drive, connector cable (NGA models only)

  10. #10
    Join Date
    May 2018
    Location
    Lancashire
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    155

    Default

    Thanks.

    Disk spins but not put anything in yet. At least something works.

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