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512K will not boot despite working diskdrive
- Thread starter BEU
- Start date
Maybe I should replace the network filter. HYTEK 8444 RC1150002 is unknown for Google. I have seen in an earlier thread that the SE/30 has a filter as described in
viewtopic.php?f=7&t=18026&hilit=bourns&start=25
I have measured the resistance between pin 2-19, 3-18 etc in my 512k and its 50 ohms so maybe it’s the same as in the SE/30? I can´t measure the capacitance.
Anybody know if I can use the same (for example Bourns 4120R-601-250/201) in the 512k?
Its available on ebay.
viewtopic.php?f=7&t=18026&hilit=bourns&start=25
I have measured the resistance between pin 2-19, 3-18 etc in my 512k and its 50 ohms so maybe it’s the same as in the SE/30? I can´t measure the capacitance.
Anybody know if I can use the same (for example Bourns 4120R-601-250/201) in the 512k?
Its available on ebay.
After some time I have continued work to get this 512k functional. I replaced the HYTEK with the Bourns 4120R-601-250/201 filter.
No change after replacement. The floppy drive is spinning but the same "happy Mac" and no booting. I checked the HYTEK filter with a resistance and capacitance meter and the HYTEK seems OK.
I have tested the logic board in a working 128k but the 512k board is not working. The boot disk (OS 2.1) and floppy drive from 512k is working with the 128k.
Any suggestions how to proced?
It would by very nice to get it working.
Greatful for any advice.
No change after replacement. The floppy drive is spinning but the same "happy Mac" and no booting. I checked the HYTEK filter with a resistance and capacitance meter and the HYTEK seems OK.
I have tested the logic board in a working 128k but the 512k board is not working. The boot disk (OS 2.1) and floppy drive from 512k is working with the 128k.
Any suggestions how to proced?
It would by very nice to get it working.
Greatful for any advice.
I tried to reseat the ROMs but no change. I have tried with both system 2.0 and 1.0. The floppy drive is working with another 512k.
The mouse is working with my defect 512K , but when I put in a floppy disk the reader starts spinning and continues to spin. The steppermotor is not moving.
I have checked the voltage(+5,+12,-12 volt) to the drive and its OK.
Is it possible to measure the signals from the logic board to the floppy drive and locate the problem???
lameboyadvance
Well-known member
Just wondering, have you tried the floppy cable in another mac as well?
Mac128
Well-known member
You said you confirmed the drive works in another Mac. The fact the stepper motor doesn't work, may hint at one problem. Check the ROMS in the other Mac you tested it in. If they are Mac Plus ROMs, or 342-022x-B then your 400K drive may require the REV B ROMs or better. Apple revised the original 64K ROM once for changes in a later model stepper motor. Im not sure exactly how this problem manifests as the drive model numbers offer little help in determining which you have. However, considering everything else you've tried, it's worth a check.
http://support.apple.com/kb/TA34190?viewlocale=en_US
Thanks Mac128 , I think You found the problem. According to Apple Support my sony drive needs the ”B” ROMs. ” "-B" ROMs are only compatible with the Sony OA-D34V-22 or OA-D34V-02 drive. Earlier drives "OA-D34V" used the "-A" ROMs” http://forums.macrumors.com/archive/index.php/t-1539356.html
The problems is that it wont work with my ”B”ROMs.
I have tried both the internal floppy drive (Sony OA—D34V-22) and an external drive (Apple M0130) connected to a Plus board ( ROM HI: 342-0341-B, ROM LOW: 342-0342-A) and everything is working perfect. Now I have two 512k boards to test.
The first 512k board (512k1) was together with the Sony drive in the Macintosh that i bought on Ebay. It was sold as not working so that is OK.
512k1 board is number 630-0118, ROM HI: 342-0220, ROM LOW: 342-0221-A. When I connect the floppy drives it will not boot. Just happy Mac, disk is spinning but stepper motor not working.
Recently I purchased another 512k board (512k2) sold as not working. 630-0118, it has ROM HI: 342-0220-B, ROM LOW: 342-0221-B. The same result when trying to boot from floppy.
The ROMs are cleaned and reseated , swithing the two ROMs between the 512k boards made no difference.
Obviously it may be better to buy working Macintosh instead, but it would be interesting to locate and solve the problem if possible.
Is it safe to put the two ROMs from the Plus board in the 512k boards?? Should it work?
Is it common that ROMs are defect??
Many thanks for all Your advice
The problems is that it wont work with my ”B”ROMs.
I have tried both the internal floppy drive (Sony OA—D34V-22) and an external drive (Apple M0130) connected to a Plus board ( ROM HI: 342-0341-B, ROM LOW: 342-0342-A) and everything is working perfect. Now I have two 512k boards to test.
The first 512k board (512k1) was together with the Sony drive in the Macintosh that i bought on Ebay. It was sold as not working so that is OK.
512k1 board is number 630-0118, ROM HI: 342-0220, ROM LOW: 342-0221-A. When I connect the floppy drives it will not boot. Just happy Mac, disk is spinning but stepper motor not working.
Recently I purchased another 512k board (512k2) sold as not working. 630-0118, it has ROM HI: 342-0220-B, ROM LOW: 342-0221-B. The same result when trying to boot from floppy.
The ROMs are cleaned and reseated , swithing the two ROMs between the 512k boards made no difference.
Obviously it may be better to buy working Macintosh instead, but it would be interesting to locate and solve the problem if possible.
Is it safe to put the two ROMs from the Plus board in the 512k boards?? Should it work?
Is it common that ROMs are defect??
Many thanks for all Your advice
volvo242gt
Well-known member
It is safe. Just turns the computer into a 512Ke. Which means, if you so choose, you can replace the 400K drive with an 800K unit and run up to System 6.0.8.
-J
-J
