is a more modern regulated power supply a better move for the TI 99 4/a?

[newTIboyRob]

So I have a few TI 99 4A's, each still in super condition. As I am not the original owner, I can't say with 100% certainty that their particular power supplies are the original ones, but they are the genuine TI parts circa 1982, that stands pretty likely. Under my care, I've never dropped anything and everything is in good working order with typical results- mild heat, faint hum, etc.

 

But, just looking for some feedback here.. I realize the power supplies for these eventually will go... but in so going, has it been common for them to send nasty power surges that would in essence kill the computer, as was/is the frying fate of the C64, or were these constructed well so that when they do eventually give out, the worst case scenario is that they are just dead, disallowing use of the computers? Don't need another ticking time bomb.

 

Thus wondering if I should replace either with more modern regulated power supplies as I did with the C64. Also had great success with a regulated 5v power supply for the NanoPeb after mulitple recommendations. So what has been your experience?  Any advice or specific replacements for these that you recommend?

 

Thanks

[+chue]

I have 3 working TIs, and at least as many parts TIs.  So probably 5 or so power supplies in total.

 

The -5V regulator in the internal power supply failed in one of working TIs and was outputting -12V.  I went looking for a replacement power supply and found one other that had the same regulator fail.  I replaced both failed -5V regulators, and the power supplies have been fine since.  Surprisingly the TI that had the failed regulator is no worse for wear.  It *seems* to be working normally.

[Kchula-Rrit]

I bought a TI in 1983 and had the power supply die in 1984, I think.  Took it apart and replaced the -5V regulator but the computer still didn't start.  Fortunately, there was a TI repair depot a few blocks from where I worked at the time.  I ran it for a few years, but then replaced it with an external supply because I was afraid of the the same thing happening again.  I recently built a new supply that seems to work okay.  It has three +5V outputs, for the CPU, USB keyboard transmitter, and the NanoPEB.

 

I have a second TI that I used as a reference system because it was totally "stock," even down to the blurry VDP chip.  The picture had been getting darker over the years, so I was afraid the VDP was dying.  I started it up a couple of weeks ago to find it apparently totally dead, no picture or start-up beep.  Disconnected the power supply and measured the voltages.  The +5V, with no load, was at +15V!  Used my bench-top supply to see if the computer was terminal and the system started up!  It will be getting another of my "new" supply boards, once I get a connector for the CPU board.

 

K-R.

[newTIboyRob]

Thanks for the stories, good to hear!  I am wondering if I am still ok to just keep using the bricks that I have or should I replace them?  (I don't want any voltage surges to damage a machine.) 

 

But if the consensus is that they are safe to still keep using because even if they go they won't damage the machine, I will keep on using. But if they are unsafe, I will replace.  What do we say here?

[JB]

1 hour ago, newTIboyRob said:

Thanks for the stories, good to hear!  I am wondering if I am still ok to just keep using the bricks that I have or should I replace them?  (I don't want any voltage surges to damage a machine.) 

 

But if the consensus is that they are safe to still keep using because even if they go they won't damage the machine, I will keep on using. But if they are unsafe, I will replace.  What do we say here?

The external bricks are pretty okay. They output unregulated AC anyways. It is rectified to DC and regulated to 5 and 12 internally. As I understand it, this "split" power supply was done for reliability purposes. The internal "coffee warmer" is more likely to fail, but I think I trust it more than the only modern replacement I've seen(which leaves the system booby-trapped for a hardware-fatal mistake).

 

As far as general failures go... how to put this politely... it turns out a company with robust minicomputer and defense industry businesses tends to construct higher-quality electronics than an office furniture company with a focus on shaving every penny? </shots_fired>

 

But seriously, my understanding is that C64 power supplies are actually exceptionally unreliable, and MOST power supplies simply don't do that.

[newTIboyRob]

@JB ... spot on, especially on the C64 power supplies. They melt like, as Robin Williams said in Mrs. Doubtfire, "a snow cone in Phoenix."  I just bought a modern version C64 power supply en route from overseas Poland as we speak. Rather wait a couple of weeks for that instead of frying the C64.

 

Ok, sounds like with the TI I will just keep going status quo then. Thanks for your input!

Edited July 21 by newTIboyRob

[Gary from OPA]

In regard to the external part of the ti99 power supply, the brick, the only ones you need to be careful of, was the original design, which Texas Instruments themselves, recalled, due to fire hazard, mainly because they would bent or fall partly out of the wall socket, and users didn't secure them in with the supplied screw, i have found now after decades of aging, any of these still left, are not wise to be used, as the transformer inside can short out, sending higher voltage to your console then it should.

 

if you have one of these pictured below, it is best to stop using it, and replaced it with the newer designed released with the two wires coming out of each side, or both at one end which was the 3rd and final design, some of those also had added on a fuse as well near the end of the AC line part.

 

 

[newTIboyRob]

Thank you @Gary from OPA   I will take photos of what I have and will post later.

[newTIboyRob]

10 hours ago, Gary from OPA said:

the newer designed released with the two wires coming out of each side, or both at one end which was the 3rd and final design, some of those also had added on a fuse as well near the end of the AC line part

Whew. After looking at all 4 bricks I have, none of them looked quite like the bottom of the bad one you posted in the photo. Photo #'s 1 and #3 have the 2 wires you said, (note that you had mentioned there were 2 wires coming out of each side, mine have the 2 wires coming only out of 1 side, not both sides), while photos #2 and #4 have the 1 wire and I see there is 1 wire at each end, (not 1 only on 1 end), thus, the ideal. Photo #1 I use with my silver model, and photos #'s 2-4 came with the beige models. Those last 3 have that shortish adapter whose plug on the end goes into the wall socket. (Is that what you meant by a fuse or is this short connecting adapter plugging in the wall something else?)

 

I think so... but I am all good here, yes?

 

 

Edited July 22 by newTIboyRob

[Gary from OPA]

18 minutes ago, newTIboyRob said:

Whew. After looking at all 4 bricks I have, none of them looked quite like the bottom of the bad one you posted in the photo. Photo #'s 1 and #3 have the 2 wires you said, (note that you had mentioned there were 2 wires coming out of each side, mine has the 2 wires coming only out of 1 side, not both sides), while photos #2 and #4 have the 1 wire but I see there is 1 wire at each end, (not 1 only on 1 end), thus, the ideal. Photo #1 I use with my silver model, and photos #'s 2-4 came with the beige models. Those last 3 have that shortish adapter whose plug on the end goes into the wall socket. (Is that what you meant by a fuse or is this short connected adapter something else?)

 

I think so... but I am all good here, yes?

 

 

Yes, you have good ones. The adapter fuse thingy looks like this:

And the latest model has the both wires coming out at the same end like in one set of your photos:

The other version you posted is good as well, has one wire at each end.

 

Now there is one other model that I have found over the years also is baddie like the plug in one I posted about earlier, this one looks like the model with both wires coming out at the same end but it doesn't have any rubber protection around the wires, notice the difference, it's also a little longer in shape not a square, this model had a habit of getting bare wires at the joint causing a short which could send the higher voltage into the wrong pins.

 

Avoid it at all costs as well. Here a picture of it.

[+OLD CS1]

10 hours ago, Gary from OPA said:

In regard to the external part of the ti99 power supply, the brick, the only ones you need to be careful of, was the original design, which Texas Instruments themselves, recalled, due to fire hazard, mainly because they would bent or fall partly out of the wall socket, and users didn't secure them in with the supplied screw, i have found now after decades of aging, any of these still left, are not wise to be used, as the transformer inside can short out, sending higher voltage to your console then it should.

I still have a couple of the wall-warts, one of which is in my travel kit as the single-cord design makes it much more able to compact for packing.

 

10 hours ago, Gary from OPA said:

it is best to stop using it

Challenge accepted.

[newTIboyRob]

@Gary from OPA Very helpful, thank you. Luckily I have no bricks like your last photo in any of my gear either. Those 3 adapters that have the green label in your photo look just like the ones I have.

 

I'd say this thread is helpful and useful for everyone here not only for the photos alone- just so we can all see what different versions of the bricks were available for the machines back then- but also adding in commentary like this from past experience/s of actual users.

Edited July 22 by newTIboyRob

[Gary from OPA]

18 minutes ago, OLD CS1 said:

I still have a couple of the wall-warts, one of which is in my travel kit as the single-cord design makes it much more able to compact for packing.

 

Challenge accepted.

It's ok if you plugging it into a power bar. The problem was the weight and long time usage when plugged in a wall socket directly, it caused some fire hazards, that's why TI was forced to recall it.

 

But overall it's stable design, except for aging and no fuse protection if something goes wrong.

 

I still wouldn't recommend it for daily 24/7 usage.

 

My ti99 systems never get powered off, they run 24/7 unless I am removing of installing a PEB card.