Search results

Voltages at the floppy port.

Did you measure the voltages at the floppy port? There are a lot of parts on classic AB that can be defect. Most often: DP3 and DP4 (1N4148), TDA4605, CNY17G, IRFBC40. And I would recap the AB.

I have a plus, a 512k and a TL866 plus or a pickit 2. I think the TL866 can program AVRs. And I have an old PS2-keyboard. I am from Germany.

DB25 in Macs is a SCSI connector, not a serial! Do not connect a serial cable to the SCSI connector!

There are a lot of parts on classic AB that can be defect. Most often: DP3 and DP4 (1N4148), TDA4605, CNY17G, IRFBC40. I would replace them all. 5V should be 4.85V for booting.

The cases are very nice! I am interested in the stl-files for 3D printing.

Lido can mount SCSI-drives too.

A2SERVER is an alternative to macip. But if you want it to use it as a file server then you need a localtalk to ethernet bridge. I use both and the A2SERVER can be seen from my windows PC. Makes it easy to download files from the internet and copy them to a mac in the localtalk net. If you like...

In a 128 FF00 means that G5 to G12 are defect and F5 to F12 are ok. Could be that one or two of your RAM modules are defect.

https://hardwaresecrets.com/how-to-generate-floppy-disks-for-old-macintosh-computers/ Windows PCs can not write 800k disks for a Macintosh!

HFV Explorer can only write 1.44 MB disks. Are you sure that you have a superdrive in your SE? 800kB disk can not be written with a Windows PC.

Schematics...

Are you sure that you harddrives and floppy disk drive and floppy disks are functional? Could you test them with another Mac?

The SE/30 has no -12V at the floppy port.

5,18 V is a little bit too high. Should be 4.85 to 5,15 V. The plus has some problems with broken solderjoints on the analog board, but I think, that the problem here is the ROM or the RAM. Perhaps someone else here in the forum has a set of ROMs for you. I could send you some, but I am from...

What are the voltages? 5V must be 4,85 V or higher for booting the plus.

Could be also a ROM problem. Sometime Plus ROMs are defect. Then you need some new burned eproms. https://www.instructables.com/Create-Macintosh-Plus-ROMs/

Reseating/Cleaning of RAM and ROM could help. Did you measure the voltages at the floppy port?

- I think you can not measure the voltages when the LB is not connected. The results may be others. - The 12 V side is also changing, if you change the 5 V side with the potentionmeter. You have to measure both when you turn the potentionmeter.

You asked for a programmer´s switch: https://www.thingiverse.com/thing:2579509