Thread
Macintosh TV sound/TV tuner problems
I was able to recap the TV tuner board itself without problems (eww! ALL of the capacitors had leaked badly), but there's a little Sony daughterboard on it (covered with small electrolytic capacitors) that gave me some troubles and I lost a few pads on it -- my guess is the leaky caps didn't help matters. Luckily the Sony daughterboard is a part commonly used in many TVs, so I can just buy a new one if I can't salvage the existing one. If I can, I plan on adding a header so replacing it in the future won't require soldering.
The Sony board is an SBX1637A-01 and appears to be for the TV audio.
Right now I'm running the newly-recapped TV tuner board without the Sony daughterboard, and the TV tuner works perfectly after being recapped! Woohoo! I'm thinking as soon as I have the Sony board recapped and back in, the TV will have sound too. Can't wait to complete this! I'm super excited to be restoring this broken Macintosh TV to its former glory
The Sony board is an SBX1637A-01 and appears to be for the TV audio.
Right now I'm running the newly-recapped TV tuner board without the Sony daughterboard, and the TV tuner works perfectly after being recapped! Woohoo! I'm thinking as soon as I have the Sony board recapped and back in, the TV will have sound too. Can't wait to complete this! I'm super excited to be restoring this broken Macintosh TV to its former glory
Haha, hope these updates aren't getting too annoying! I was able to repair the sony sound board's missing pads and recap it. The TV sound is there now, but very very faint. I probably screwed something up along the way. My plan is to just buy a new sound board. That board has a TON of capacitors on it; it was really difficult to recap. I'm sad that it didn't work 
But I'm not overly upset about it. Other sources online for TV repair said to just buy a new module and don't bother recapping it. I see why -- it's so jam-packed!
But I'm not overly upset about it. Other sources online for TV repair said to just buy a new module and don't bother recapping it. I see why -- it's so jam-packed!
Replaced the Sony sound board, and added a socket (found some 0.070" pitch headers on Digi-Key) so if it has to be replaced in the future, no desoldering will be necessary.
The TV sound is alive again! Woohoo! Haven't tested the floppy or CD drive, but everything else is perfect aside from the nasty hard drive sound when it first spins up (and when it spins down). Anyway, awesome! Mission accomplished before analog cable is completely gone.
The TV sound is alive again! Woohoo! Haven't tested the floppy or CD drive, but everything else is perfect aside from the nasty hard drive sound when it first spins up (and when it spins down). Anyway, awesome! Mission accomplished before analog cable is completely gone.
When they make the switch you can still get OTA local channels with a $20 digital converter box.
Some of my local channels look as good (or better than) HD on cable when we had it.
Some of my local channels look as good (or better than) HD on cable when we had it.
That's true...also, bbraun told me there are devices that take composite and s-video inputs and turn them into analog TV channels. That would be interesting to try too.
Here's a video of the Mac TV in action:
Here's a video of the Mac TV in action:
That's a cool TV! Just a few questions though:
Why did it show the happy Mac twice?
Why was the clock not set (I assume there's no PRAM battery, but am I correct)?
Is the TV flicker due to changing channels, or is that how it looks when on one channel (I'm not talking about the strobing effect on all screens)?
Why are you using that remote, not the original (I guess that's not the original)?
Why did it show the happy Mac twice?
Why was the clock not set (I assume there's no PRAM battery, but am I correct)?
Is the TV flicker due to changing channels, or is that how it looks when on one channel (I'm not talking about the strobing effect on all screens)?
Why are you using that remote, not the original (I guess that's not the original)?
Thanks!
Your first and second questions are actually related. Both happen because I don't have a PRAM battery installed. When a Mac with uninitialized PRAM first boots up, it's in 24-bit addressing mode. If you try to boot into System 7.6 with 24-bit addressing, it will chime and show the Happy Mac, and then it will put the Mac into 32-bit mode and reboot. So that's why you hear the second chime -- it's System 7.6 changing to 32-bit addressing. The clock was also not set because there's no PRAM battery. I don't know why the "clock not set" message immediately dismisses itself. Maybe it's special behavior in the Mac TV? Or do other computers do that too?
The flickering is definitely due to the CRT being filmed by my phone. I don't notice any blinking when I watch with my eyes.
The remote I'm using is the original remote. Newer systems with TV cards had a different style of remote which is also compatible with the Mac TV's remote, but the remote I have was the type Apple originally included with the Mac TV.
Your first and second questions are actually related. Both happen because I don't have a PRAM battery installed. When a Mac with uninitialized PRAM first boots up, it's in 24-bit addressing mode. If you try to boot into System 7.6 with 24-bit addressing, it will chime and show the Happy Mac, and then it will put the Mac into 32-bit mode and reboot. So that's why you hear the second chime -- it's System 7.6 changing to 32-bit addressing. The clock was also not set because there's no PRAM battery. I don't know why the "clock not set" message immediately dismisses itself. Maybe it's special behavior in the Mac TV? Or do other computers do that too?
The flickering is definitely due to the CRT being filmed by my phone. I don't notice any blinking when I watch with my eyes.
The remote I'm using is the original remote. Newer systems with TV cards had a different style of remote which is also compatible with the Mac TV's remote, but the remote I have was the type Apple originally included with the Mac TV.
Clock not set happens on my 5400 series also. Sometimes its fast, sometimes not. I think sometimes its a disc access issue kinda like it had not loaded the control panel at the same rate during boot. Like the G3 accelerator changed the behavior even more.
Mine does that as well! I've often wondered why... :?: :?:
I'm not refering to the general flicker. There's a much slower "sweep" effect, repeating about once every 2 seconds, during the TV tuner demonstration. I couldn't quite tell if you were changing channels there or not.
Then that's a very modern-looking remote! It looked out-of-place with the Mac TV, so I assumed it was not the original.
That sweep is just occurring every time I change the channel. When you stay on a single channel it doesn't do that
Yeah, it is a pretty cool-looking remote! I think it can also control playing audio CDs, although I haven't tried that yet.
Yeah, it is a pretty cool-looking remote! I think it can also control playing audio CDs, although I haven't tried that yet.
It reminds me of when I used a 638CD with the tuner card as a bedroom TV for a few years. My TAM doesn't pick up any stations here at the office.
Faint sound is almost always the SMT electrolytics on the motherboard, those things are horrible. I would replace the ones in the tuner as well, there is a good chance that replacing ALL of the SMT lytics with tantalum or ceramic capacitors will resolve all of your problems.
I've also found that the large through-hole electrolytics rarely fail, only those that are in the output filters of the power supply. The big ones I only replace if they test marginal or bad, the smaller ones in the power supply and any surface mount electrolytics get replaced wholesale. It's not even worth troubleshooting until you do that.
I've also found that the large through-hole electrolytics rarely fail, only those that are in the output filters of the power supply. The big ones I only replace if they test marginal or bad, the smaller ones in the power supply and any surface mount electrolytics get replaced wholesale. It's not even worth troubleshooting until you do that.
Yep, that's exactly what it ended up being--bad SMT electrolytics on the logic board and tuner board. I don't think the analog board needed a recap at all, but I'm not upset about doing it. I smelled a fishy smell when removing some of the caps, so it was probably a good idea. Still need to fix the focus adjustment after the analog board recap though...picture is still slightly blurry.
I stuck with replacement electrolytics. I'm well aware it will have to be recapped again, and I'm OK with that.
I stuck with replacement electrolytics. I'm well aware it will have to be recapped again, and I'm OK with that.