Twentieth Anniversary Macintosh tuner board burned

[guibrush]

Hi,
I exposed my TAM the last week-end on a booth at the OCCF in Switzerland, and unfortunately for me, something bad happened to my TAM: If refused to power on, meaning that the green LED under the Subwoofer came to life and immediately went down again, meaning that the power supply was certainly going in protection mode. Several try to power on brought an explosion in the TAM (ouch). I dismantled it and could locate the problem on the tuner board (if you see the pic, it's obvious ). I removed the tuner board and plugged everything back again. Now the power supply stay on, no more protection mode, but the TAM refuse to boot, with the HDD (well, in my case the SD card adapter) LED staying on. No boot sound.
I'm wondering if the TAM need the tuner board to be able to boot? Does anyone know that?

Otherwise, I checked the battery pack, I have 4.7V coming in. I'm trying no to let rest the computer for 48h without being plugged in and without battery so see if it help. Does anyone have another idea what. could check?
Thanks for your help!

 

[Byrd]

Oh dear - it's just the tantalum capacitor by all appearances - looks like the same markings at the one opposite, 10V 100uF (at a guess). I wouldn't think you'd need it for boot - the 6500 it is based off also has a separate TV tuner box and not essetial.

I'd pull the PRAM battery press the CUDA reset switch on the motherboard and leave it be for an hour. Come back with the PRAM battery plugged back in and fingers crossed it'll chime and power up (without the TV tuner).

 

[ObeyDaleks]

Not familiar with the TAM circuitry, but that blown tantalum can be causing a short. I would definitely remove/replace it before doing anything else. Also, I would check the ferrite bead next to it at L4 for continuity.

 

[guibrush]

ok, trying to power on the TAM after a reset procedure (disconnecting the battery pack, pressing the button on the Mobo and letting rest the TAM unplugged for some hours) didn't helped at first. Then I disassembled totally the motherboard to see if somethings else was burned, everything's looked fine. I reassembled the machine, and it booted. No idea why. But I can confirm that the TAM can boot without the tuner board. As this board is now totally obsolete (no more FM and no more analogue TV on the cable), I will call it a day and let it outside the computer. Thanks for the help!

 

[pizzigri]

As this board is now totally obsolete (no more FM and no more analogue TV on the cable), I will call it a day and let it outside the computer. Thanks for the help!

while I sure agree on the analog TV, sorry to say but regarding FM what are you talking about?
FM is still used all across EU and I can still use a 1970 Toshiba receiver for hifi audio today

 

[Unknown_K]

Looks to me like 3 components burned judging by the melt marks on that plastic.
C15, L4, and probably C98 (looks cracked).

The issue you will have is which one blew taking the rest with them.

 

[guibrush]

while I sure agree on the analog TV, sorry to say but regarding FM what are you talking about?
FM is still used all across EU and I can still use a 1970 Toshiba receiver for hifi audio today

I'm in Switzerland, we have no FM anymore sadly.

 

[chelseayr]

I have to say @guibrush indeed is correct, and for anyone curious it seem like norway and switzerland and part of north side of germany all have definitive plans to move from fm to dab+
(there may be more and/or better details but I'll leave that to someone else due to me shortly going out for the day)

 

[Byrd]

Glad it's working - I've had similar issues with my TAM after some upgrades resulting in a "dead" Mac, but disconnecting all and letting it think it always gets back. Still looks like a single tantalum cap has blown (as they do) and once the soot is removed other components look OK.

There used to be a legitimate Mac parts website based in Netherlands that sold a small lot of Apple TAM parts, but I can't find it any more. Either way, you could also probably adapt the TV tuner from a 6500 but it lacks FM functionality.

Amazed FM radio is being phased out - in Australia we still have AM and reported to stay assume due to needing long range signals of our vast country.

 

[guibrush]

yup, looks like the "let it rest without battery" trick saved many users, me included
Yes, in Switzerland the FM is already history unfortunately. Only DAB+ now. This is causing many troubles, as people have to change all radio devices.

 

[pizzigri]

In Italy it’s expected to survive at least through 2035….

 

[croissantking]

In UK we’re safe till after 2030.

When it does happen what will I do with my beloved Technics ST-600L?

 

[CC_333]

We here in the US will probably be able to enjoy analog Am and FM forever.

It's the content that's disappearing. Ultra conservative talk, religious preaching and ethnic programming aren't my thing, and that's like 90% of what AM is putting out nowadays.

FM still has some life in it, but it's heading for the same fate as a wasteland of stuff that nobody wants to listen to.

When it does happen what will I do with my beloved Technics ST-600L?

Perhaps you can invest in a little FM transmitter thing and hook a DAB+ radio up to it. Then you can enjoy a small, hopefully legal bubble of warm and cozy analog in an otherwise cold and hostile all-digital world.

c

 

[adespoton]

We here in the US will probably be able to enjoy analog Am and FM forever.

It's the content that's disappearing. Ultra conservative talk, religious preaching and ethnic programming aren't my thing, and that's like 90% of what AM is putting out nowadays.

FM still has some life in it, but it's heading for the same fate as a wasteland of stuff that nobody wants to listen to.


Perhaps you can invest in a little FM transmitter thing and hook a DAB+ radio up to it. Then you can enjoy a small, hopefully legal bubble of warm and cozy analog in an otherwise cold and hostile all-digital world.

c

I have a mini FM transmitter for my car that pre-dates CarPlay. I can plug my modern-ish phone into it and broadcast to all FM receivers within a 6' radius!

I also successfully plugged a Bluetooth audio adapter into it, so now any device can send it Bluetooth audio and have that come out as FM. Higher channels have higher fidelity.