Quadra 610

[iigs123]

I think I found the issue: U25, a F245 bus transceiver. This was next to a leaky cap. I thought I had it clean enough, but when I went over the area again one of the legs fell off :/

Based on the block diagram of the 610 this would probably cause issues reading the ROM at startup.

 

[Phipli]

I think I found the issue: U25, a F245 bus transceiver. This was next to a leaky cap. I thought I had it clean enough, but when I went over the area again one of the legs fell off :/

Based on the block diagram of the 610 this would probably cause issues reading the ROM at startup.

Yeah, that area doesn't look great. The vias next to the 'C50' text specifically was the thing that made me decide to ask for more photos.

 

[iigs123]

Two legs ended up falling off. The pads on the board are damaged too, from the looks of things the trace and thru-hole as well. Seems like this might not be easily repairable. I'm also not sure where to get a replacement F245.

 

[Phipli]

Two legs ended up falling off. The pads on the board are damaged too, from the looks of things the trace and thru-hole as well. Seems like this might not be easily repairable.

Its in better condition than mine was! You can do this, don't worry

You might be able to tack a component lead to the pin stubs. Otherwise, a new part.

Do you have a hot air gun? Or know anyone with one? Removing the chip and replacing it gives a chance to clean underneath.

I'm also not sure where to get a replacement F245.

Oh, anywhere. They're common. eBay is probably the best solution for small quantities, although that might cause quality issues. Buy at least two.

They're a really common part the 74F245. Do you have any completely trashed macs? They'll probably have some. But new parts is easier.

Pad repairs aren't too bad either. Once the new component is in, I'd run insulated enamelled wire from the pins to somewhere suitable.

Bad vias are often fixed by clearing the solder out of them and running small gauge wire through the hole and soldering it both sides.

 

[iigs123]

Its in better condition than mine was! You can do this, don't worry

You might be able to tack a component lead to the pin stubs. Otherwise, a new part.

Do you have a hot air gun? Or know anyone with one? Removing the chip and replacing it gives a chance to clean underneath.

Oh, anywhere. They're common. eBay is probably the best solution for small quantities, although that might cause quality issues. Buy at least two.

They're a really common part the 74F245. Do you have any completely trashed macs? They'll probably have some. But new parts is easier.

Pad repairs aren't too bad either. Once the new component is in, I'd run insulated enamelled wire from the pins to somewhere suitable.

Bad vias are often fixed by clearing the solder out of them and running small gauge wire through the hole and soldering it both sides.

I should start by saying that I do not have plans to trash anything- the case and other parts are quite nice actually. I do not have any other boards to salvage from just yet.

I was able to remove the bad part by overflowing with solder, but it looks like there was other damage to the board. The contrast isn't great but take a look:



I'll need my super vision to trace this on the back of the board!

 

[Phipli]

I should start by saying that I do not have plans to trash anything- the case and other parts are quite nice actually. I do not have any other boards to salvage from just yet.

I was able to remove the bad part by overflowing with solder, but it looks like there was other damage to the board. The contrast isn't great but take a look:

View attachment 58028

I'll need my super vision to trace this on the back of the board!

If you find the other side of the broken via, follow the trace (with a continuity tester), often it will pop up again on the first side, allowing you to just run a wire from the chip pin to where the trace ultimately goes, or perhaps tack it to another via further down the same trace where it is convenient.

 

[Phipli]

I should start by saying that I do not have plans to trash anything- the case and other parts are quite nice actually. I do not have any other boards to salvage from just yet.

I was able to remove the bad part by overflowing with solder, but it looks like there was other damage to the board. The contrast isn't great but take a look:

View attachment 58028

I'll need my super vision to trace this on the back of the board!

One thing, I strongly recommend not removing chips with an iron, its very likely to result in removing pads. It softens the bond between the pad and the board and you can't easily get heat into all of the solder at once. You get a snag and the pad comes off.

The one exception is probably when using ChipQuik.



The broken trace comes back up under the clock G3, I'll check where else...

 

[Phipli]

Found a handy location. It is available on the unpopulated ROM SIMM connector. 7th pin from the left on the lower row, when looking with the silkscreen text the right way up. Once you have a replacement chip in place you can run a bodge wire between pin 2 on the chip and that location. But be super careful with the RAM slots, the plastic is super melty. Avoid touching it at all costs.



Yes, I don’t have any onboard RAM. Ignore that. I took it off while troubleshooting and never put any back.

You also need to check other traces from pads to destination to make sure, for example, that the trace from pin 1 isn't broken.

 

[iigs123]

Thank you for the assistance. I'll need to order a couple of things, including the replacement part, so it will be a bit of time before I can report back.

 

[iigs123]

Ebay seems pricey for two parts. I'm not very familiar with these parts- is this an equivalent?

https://www.digikey.com/en/products/detail/texas-instruments/SN74F245DBR/373705

 

[Phipli]

Ebay seems pricey for two parts. I'm not very familiar with these parts- is this an equivalent?

https://www.digikey.com/en/products/detail/texas-instruments/SN74F245DBR/373705

I for me the postage on anything from Digikey would be way more than the price of the parts, have you accounted for that?

The part looks superficially the same, but you really need to verify such things yourself with the datasheet.

 

[iigs123]

Found a handy location. It is available on the unpopulated ROM SIMM connector. 7th pin from the left on the lower row, when looking with the silkscreen text the right way up. Once you have a replacement chip in place you can run a bodge wire between pin 2 on the chip and that location. But be super careful with the RAM slots, the plastic is super melty. Avoid touching it at all costs.

View attachment 58039

Yes, I don’t have any onboard RAM. Ignore that. I took it off while troubleshooting and never put any back.

You also need to check other traces from pads to destination to make sure, for example, that the trace from pin 1 isn't broken.

I think my pin 1 is broken too. Do you know where it leads? It looks like it comes back up under U24.

 

[Phipli]

I think my pin 1 is broken too. Do you know where it leads? It looks like it comes back up under U24.

Just clean it and put a blob of solder on it. Its only a flesh wound.

 

[iigs123]

I'm happy to say that the chip is replaced, and I'm now getting a startup chime! I'm messing with the VGA adapter to try to get a picture. So far it is either no signal or fuzzy gray.

Thank you for your help, I really appreciate it.

 

[iigs123]

I redid all of the capacitors and the bodge wire, cleaned carefully, and re-seated the CPU. Now i'm booting System 7.5.3 via blue scsi. Thank you for your advice and encouragement!

 

[Phipli]

I redid all of the capacitors and the bodge wire, cleaned carefully, and re-seated the CPU. Now i'm booting System 7.5.3 via blue scsi. Thank you for your advice and encouragement!

Excellent news They're nice machines.

Is it a 20 or a 25MHz variant? Does it have ethernet?

 

[iigs123]

25 Mhz, with ethernet. The etherwave and my ASUS router show link lights, but MacTCP is quite unfriendly to setup so I don't have a network connection yet. But BlueSCSI seems just fine for now.

 

[Phipli]

25 Mhz, with ethernet. The etherwave and my ASUS router show link lights, but MacTCP is quite unfriendly to setup so I don't have a network connection yet. But BlueSCSI seems just fine for now.

MacTCP doesn't support DHCP, so you'll need to enter a manual ip in the control panel, or use OpenTransport, which supports DHCP.

 

[iigs123]

I was trying OpenTransport, but neglected to uncheck the "Load only when needed" box to test pings. It seems to be working now.

 

[iigs123]

Well I guess I had to turn the dials to 11 on this Quadra. I was playing with NetBSD, and waiting for it to generate SSH host keys while doing other things. I tapped the keyboard every now and then and it was still chugging away. It was doing this for quite a while. SSH might have been silly but I was eventually going to try to compile some things, expecting lengthy compile times. Then, I tapped the keyboard and it was locked up solid. When I powered down, waited a little bit and tried to power up I failed to get any chimes.

I opened the cover and nothing looks exploded. The CPU was only slightly warm, not scalding at all. No smoke, no pops, nothing.

I removed the ram and tested the caps again to see if any solder had a bad joint, and touched up a few joins but things seemed to be OK. The PSU is testing fine still. Oh, and the CPU does still get slightly warm when I turn it on.

Is it possible I cooked the CPU? Or maybe the bus transceiver I replaced couldn't handle the extended load?

It was fun while it lasted!