Mac Classic - will it ever run again!!

[rubber_jonnie]

Ok, so I watched an interesting video on Adrians Digital Basement the other day: https://www.youtube.com/watch?v=pvjsXbz1xlk

In it he uses RGB2HDMI to connect a Mac Classic to HDMI.

It's pretty simple to do , but I think the same thing will offer me a chance to at least verify that my Classic boards run ok and see them on an HDMI display.

The problem is, I'm not confident that the Analog board is good, so if I can power the mainboard off a bench PSU, and get video out as he did, then I can at least verify I have a good mainboard and attack the Analog board.

Since @Tomswork did send me a good board, which just requires some new caps IIRC, I can start there.

There are some exciting projects around at the moment, so looking forward to getting my new workshop up and running to get some of this stuff done

Not 100% sure what I'll do if the analog board and tube are toast, but one step at a time, verify the mainboard and then see what's next.

Since everything is in storage at the moment anyway, all I can do is formulate my plans, and at least line up the RGB2HDMI bits. I do also have an OSSC already and it may also work with that with no need for RGB2HDMI.

Since I got the OSSC relatively recently, and guess what, that's in storage too, I haven't fully got my head around things, so we'll see.

[stephen_usher]

Well, if the analogue board is toast then you can potentially fit an LCD display in the case along with an alternative PSU and drive the LCD using an RGBtoHDMI board. Just a thought.

[rubber_jonnie]

Well, if the analogue board is toast then you can potentially fit an LCD display in the case along with an alternative PSU and drive the LCD using an RGBtoHDMI board. Just a thought.

Indeed I could, and the thought had crossed my mind, and though it would be nice to get it working as a whole, CRT and all, I'll take what I can get if it gets it up and running again.

[Tomswork]

The only part that is hard to source on the mac classic analog board is the flyback. If it is ok every thing else can be fixed. Trace breaks and bad solder joints are the most common problems after the capacitors. Then the ic and diodes. Almost all of those can be checked with a meter there is one resistor if I remember that goes out of spec on that board too.

Tom

[rubber_jonnie]

The only part that is hard to source on the mac classic analog board it the flyback. If it is ok every thing else can be fixed. Trace breaks and bad solder joints are the most common problems after the capacitors. Then the ic and diodes. Almost all of those can be checked with a meter there is one resistor if I rember that goes out of spec on that board to.

Tom

I'll review properly once I'm in my new workshop and have all the bits to hand. I still need to unpack your board as it pretty much arrived as we were packing to move.

First thing on the bench when we get in the new place.

[rubber_jonnie]

Ok, it's been a while, but the classic is back on the workbench!!

Last time it was out, it was at the old place, but we are ready to go now!!

IMG_20211214_142850.jpg (196.46 KiB) Viewed 2050 times

Lets hope that with the help of the logic board from @Tomswork this little beauty will live again!!

[Tomswork]

Here is hoping for a easy repair

Tom

[stephen_usher]

Good luck!

The biggest problem is trying to get these boards in a position to test due to the length of the cables.

I guess that the main board will run with just +5V and Ground.

I s'pose you could de-solder the power/video cable from the analogue board and install longer wires and solder the original connector wires to that. I may do this with my SE/30 which has an issue with its SCSI interface.

[rubber_jonnie]

Here is hoping for a easy repair

Tom

I think there may also be problems with the analogue board too (I've recapped your board BTW), when the mainboard is connected, the HDD won't power up, when disconnected it will, plus the CRT tube heater isn't coming on.

The main thing that I need to do is go and look at the dead Mac scrolls, see if I can get a read. It's almost like there's a short, but it does it with any mobo, hence why I think it's an analogue board issue. BTW that has been recapped too.

About the only thing that works is the fan!!

[rubber_jonnie]

Good luck!

The biggest problem is trying to get these boards in a position to test due to the length of the cables.

I guess that the main board will run with just +5V and Ground.

I s'pose you could de-solder the power/video cable from the analogue board and install longer wires and solder the original connector wires to that. I may do this with my SE/30 which has an issue with its SCSI interface.

Yeah, the short cables put you in rather close proximity to the flyback which isn't fun at all!!

I need to dig out my docs/schematics again to remind myself of what's going on. I also seem to recall I bought an IC for the analogue board so need to dig that out too.