Re: TI994/A Power Supply
If somebody found a mains cord that "fits" and plugged it in with the low voltage AC input connected to the wall, then it might not be happy now. You might want to avail yourself of some of Allison's expertise. Might I suggest a box of 8" floppies for XMAS? On Fri, 15 Nov 2019, allison via cctalk wrote: Omph, Its close enough to the Early HP detachable cord and yes if thats done (could not scream nooo loud or fast enough) the result is both load and spectacular. And, the machine and cord get thrown into a box in the back of a closet. Eventually, somebody else gets it, and sees that it has a cord, . . . I have a crate of 8" used and a box or two of NIB. They seem to last if they don't say noname or Memorex blackwatch ;) I use them more for RX01/02. Price these days is probably similar to what it was 45 years, ago. And availability is heading towards what it was 50 years ago.
Re: TI994/A Power Supply
On 11/15/19 1:29 PM, Fred Cisin via cctalk wrote: > On Fri, 15 Nov 2019, Jules Richardson via cctalk wrote: >> OK, the cord "fits", but having looked at it now I'm not at all >> convinced, either. The two-pin socket is actually the same as the >> four-pin socket on the other two machines, but with the upper two pins >> (intentionally) missing. >> The PSU board inside appears to be a switcher, but I'd be inclined to >> agree with Allison that it's intended to run from low-voltage AC (I've >> put the machine back together now, but just realized that I should >> have checked the voltage rating on the rectifier stage's caps). > > If somebody found a mains cord that "fits" and plugged it in with the > low voltage AC input connected to the wall, then it might not be happy now. > > You might want to avail yourself of some of Allison's expertise. > Might I suggest a box of 8" floppies for XMAS? > > Omph, Its close enough to the Early HP detachable cord and yes if thats done (could not scream nooo loud or fast enough) the result is both load and spectacular. I forget the ideal voltage though. The only transformer are ones floating loose are the 4pin plug versions. But there are TI 99/4A sites on the net with all that. I have a crate of 8" used and a box or two of NIB. They seem to last if they don't say noname or Memorex blackwatch ;) I use them more for RX01/02. Allison
Re: TI994/A Power Supply
On Fri, 15 Nov 2019, Jules Richardson via cctalk wrote: OK, the cord "fits", but having looked at it now I'm not at all convinced, either. The two-pin socket is actually the same as the four-pin socket on the other two machines, but with the upper two pins (intentionally) missing. The PSU board inside appears to be a switcher, but I'd be inclined to agree with Allison that it's intended to run from low-voltage AC (I've put the machine back together now, but just realized that I should have checked the voltage rating on the rectifier stage's caps). If somebody found a mains cord that "fits" and plugged it in with the low voltage AC input connected to the wall, then it might not be happy now. You might want to avail yourself of some of Allison's expertise. Might I suggest a box of 8" floppies for XMAS?
Re: TI994/A Power Supply
On 11/15/19 7:46 AM, Jules Richardson via cctalk wrote: > On 11/14/19 3:02 PM, Jules Richardson via cctalk wrote: >>> I'm about 95% certain that it does NOT take line voltage in. >> >> Hmm, I'll see if I can find a moment to take it apart later. It's >> interesting that it's a boxed unit with a cord that fits - but then it >> does have three broken keys (caps are kicking around in the box) so >> it's entirely possible that someone just parked it there for storage. > > OK, the cord "fits", but having looked at it now I'm not at all > convinced, either. The two-pin socket is actually the same as the > four-pin socket on the other two machines, but with the upper two pins > (intentionally) missing. > > The PSU board inside appears to be a switcher, but I'd be inclined to > agree with Allison that it's intended to run from low-voltage AC (I've > put the machine back together now, but just realized that I should have > checked the voltage rating on the rectifier stage's caps). Your inclined to agree, seriously. I have at least one of every model and have run them periodically for the games, refresh the media (tape and disks) and also because its collection. I have all the available documents including user and service manuals. I've even gone as far as to make a hybrid high speed system with 16bit wide memory. When you have excess a few hacked for fun. FOor those that gasp and clutch their chest I use the black model as they are common as house flies. The base early 99/4 and the late beige model are uncommon. That and ratshack used to sell the switcher, transformer, keyboard after TI quit and parted out their stock. I have a few of all. Allison
Re: TI994/A Power Supply
On 11/14/19 3:02 PM, Jules Richardson via cctalk wrote: I'm about 95% certain that it does NOT take line voltage in. Hmm, I'll see if I can find a moment to take it apart later. It's interesting that it's a boxed unit with a cord that fits - but then it does have three broken keys (caps are kicking around in the box) so it's entirely possible that someone just parked it there for storage. OK, the cord "fits", but having looked at it now I'm not at all convinced, either. The two-pin socket is actually the same as the four-pin socket on the other two machines, but with the upper two pins (intentionally) missing. The PSU board inside appears to be a switcher, but I'd be inclined to agree with Allison that it's intended to run from low-voltage AC (I've put the machine back together now, but just realized that I should have checked the voltage rating on the rectifier stage's caps). cheers Jules
Re: TI994/A Power Supply
On 11/11/19 1:12 AM, Eric Smith via cctalk wrote: On Sat, Nov 9, 2019 at 1:46 PM Jules Richardson via cctalk < cctalk@classiccmp.org> wrote: I've got another /4A however which has a 2-pin plug on the back, and that one appears to just take plain ol' 110VAC line voltage and the PSU is completely internal (at least, there's a power cord with it which fits, but that one has a few broken keys and so I've never actually done anything with it). I'm about 95% certain that it does NOT take line voltage in. Hmm, I'll see if I can find a moment to take it apart later. It's interesting that it's a boxed unit with a cord that fits - but then it does have three broken keys (caps are kicking around in the box) so it's entirely possible that someone just parked it there for storage. cheers Jules
Re: TI994/A Power Supply
On 11/11/19 2:12 AM, Eric Smith via cctalk wrote: > On Sat, Nov 9, 2019 at 1:46 PM Jules Richardson via cctalk < > cctalk@classiccmp.org> wrote: > >> I've got another /4A however which has a 2-pin plug on the back, and that >> one appears to just take plain ol' 110VAC line voltage and the PSU is >> completely internal (at least, there's a power cord with it which fits, >> but >> that one has a few broken keys and so I've never actually done anything >> with it). >> > > I'm about 95% certain that it does NOT take line voltage in. It just has a > different internal power supply assembly that only uses one of the > low-voltage AC inputs from the external power supply instead of both. As > far as I've ever heard, there was no 99/4 or 99/4A that did not use an > external power supply. > > If it were mine, I wouldn't even consider pluging it into line voltage > until doing a lot more research on exactly what's inside. > I have at least a few 99/4, 99/4a(black), 99/4a (beige cost reduced). NONE of the 99/4 or 99/4a take line in. They differ in the power supply used internally and the brick externally. The two pin uses a single AC voltage brick (dc can be used of correct votlage) and the other uses two windings. How do the two supplies differ is one is linear and old school for the three votlages (+12,+5, -5) and the other is a low voltage switcher based on the 424 IC. NEVER connect the two pin console to 100 or 230V without the transformer. Or you will have a fire hazard! Allison
Re: TI994/A Power Supply
On Sat, Nov 9, 2019 at 1:46 PM Jules Richardson via cctalk < cctalk@classiccmp.org> wrote: > I've got another /4A however which has a 2-pin plug on the back, and that > one appears to just take plain ol' 110VAC line voltage and the PSU is > completely internal (at least, there's a power cord with it which fits, > but > that one has a few broken keys and so I've never actually done anything > with it). > I'm about 95% certain that it does NOT take line voltage in. It just has a different internal power supply assembly that only uses one of the low-voltage AC inputs from the external power supply instead of both. As far as I've ever heard, there was no 99/4 or 99/4A that did not use an external power supply. If it were mine, I wouldn't even consider pluging it into line voltage until doing a lot more research on exactly what's inside.
Re: TI994/A Power Supply
On 11/4/19 7:39 AM, Allison Parent via cctalk wrote: Do better research. The power is external transformer and internal low voltage switch mode power supply. It seems to depend on the variant. I've got a /4 and a /4A which have 4-pin plugs on the back, and these use an external PSU outputting 18VAC and 8.5VAC. I've got another /4A however which has a 2-pin plug on the back, and that one appears to just take plain ol' 110VAC line voltage and the PSU is completely internal (at least, there's a power cord with it which fits, but that one has a few broken keys and so I've never actually done anything with it). cheers Jules
Re: TI994/A Power Supply
Do better research. The power is external transformer and internal low voltage switch mode power supply. Having carts is good. The bonus is an expansion box with floppy and cards. FYI back when ratshack sold both. Allison IPhoned it in! > On Nov 4, 2019, at 12:59 AM, Kevin Parker via cctalk > wrote: > I may be stating the obvious here but looking for a little advice and reassurance from anyone on the list who may have had experience with these machines. I have a couple of TI99/4A's that I was given quite a long time ago along with about 50 software cartridges (if I understand things correctly the cartridges on their own a quite a bonus). What I am missing are power supplies. On my research the inputs are 12 and/or 5 volt depending on the number of power pins on the back (mine have 2). These voltages appear to neatly align with most PC power supplies so I should be able to tap into an old AT power supply of which I have quite a few. Thank you. Kevin Parker
Re: TI994/A Power Supply
> On November 4, 2019 at 5:12 AM Liam Proven via cctalk > wrote: > > On Mon, 4 Nov 2019 at 06:59, Kevin Parker via cctalk > wrote:>>> These voltages appear to neatly align with most PC power supplies > so Ishould be able to tap into an old AT power supply of which I have quite > afew.The PSU apparently outputs AC, not DC, which is unusual... but a PCPSU > can do it, and Molex connectors can be bodged into fitting. > Does this help? > http://oldcomputer.info/8bit/ti99/index.htm > Schematic:http://www.mainbyte.com/ti99/hardware/power_supply.html A couple of notes. First, I'm not all too familiar with the TI, but I was always under the impression the PS provided +5 and +12 DC. For a while in the 80s the power supply module was available separate (even from Radio Shack!) and I bought one. I did a quick search and found the same site Liam linked above. It shows a schematic of a transformer providing 8 and 16 VAC, but then also mentions that there are various schematics floating around and that the author has been told his is non-standard. It does also mention, however, that the machine uses 4116 RAM which requires -5V as well. The summary is that I would make real sure what it takes before connecting anything. If it does indeed need AC, it may use the AC internally to regulate -5V and providing DC could damage the RAM. Another note is that many PC power supplies will have a minimum required load that the TI may not meet. Some will simply not power on if the load isn't met, but I have seen a few that will provide unregulated voltage. Been a while since I saw one of those, though. but do be careful. Will "A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away." -- Antoine de Saint-Exupery "The names of global variables should start with// " -- https://isocpp.org
Re: TI994/A Power Supply
On Mon, 4 Nov 2019 at 06:59, Kevin Parker via cctalk wrote: > > > These voltages appear to neatly align with most PC power supplies so I > should be able to tap into an old AT power supply of which I have quite a > few. The PSU apparently outputs AC, not DC, which is unusual... but a PC PSU can do it, and Molex connectors can be bodged into fitting. Does this help? http://oldcomputer.info/8bit/ti99/index.htm Schematic: http://www.mainbyte.com/ti99/hardware/power_supply.html -- Liam Proven - Profile: https://about.me/liamproven Email: lpro...@cix.co.uk - Google Mail/Hangouts/Plus: lpro...@gmail.com Twitter/Facebook/Flickr: lproven - Skype/LinkedIn: liamproven UK: +44 7939-087884 - ČR (+ WhatsApp/Telegram/Signal): +420 702 829 053
