PDA

View Full Version : Mhz display help



Amigaz
March 7th, 2008, 11:55 AM
On my recently aquired Baby AT tower there's a Mhz display which I believe is inproperly connected since it doesn't show the numbers correctly and there's some spare wires that I think should be connected to it.
I think this is a longshot but does someone have any idea what all these pins are and what to connect to them?

http://img156.imageshack.us/img156/1918/p1010318pe2.jpg

kb2syd
March 7th, 2008, 12:32 PM
Typically, the green provides power to the display unit.

The two blacks indicate if it is in turbo or non-turbo mode.

The jumpers then set which LEDs are on for each mode. I think there are 2 jumpers for each segment, one for turbo, one for non-turbo.

Hope this helps.

IBMMuseum
March 7th, 2008, 12:34 PM
On my recently aquired Baby AT tower there's a Mhz display which I believe is inproperly connected since it doesn't show the numbers correctly and there's some spare wires that I think should be connected to it.
I think this is a longshot but does someone have any idea what all these pins are and what to connect to them?...

"All these pins" are jumper pins. Start playing around to adjust to the correct MHz speed you want to display. It's just a trial and error thing.

carlsson
March 8th, 2008, 12:40 AM
Or you can form any numbers or letters you want to display. Back in the days, I liked to configure those displays to read out AC (my initials), in particular on early Pentiums who ran faster than 99 MHz anyhow and no longer had any turbo mode.

IBMMuseum
March 8th, 2008, 02:46 PM
Or you can form any numbers or letters you want to display. Back in the days, I liked to configure those displays to read out AC (my initials), in particular on early Pentiums who ran faster than 99 MHz anyhow and no longer had any turbo mode.

For the ultimate idea of LED MHz display there is the IBM PS/2 Model 95 (the larger case Server 500 and Server 720 have the same or better capabilities too): http://www.youtube.com/watch?v=WqxRBAbbCzs&NR=1

There has even been a driver written to display specific data or design a marquee-style display...

fred333
April 10th, 2008, 07:43 AM
Thanks for the link to the video.

the xt guy
April 15th, 2008, 06:36 PM
Here is a link to a page which tells how to program the case display

http://www.pcmech.com/article/how-to-program-your-system-case-display/

Mad-Mike
April 16th, 2008, 06:54 AM
If that readout page doesn't look good, I'm going to be making one for my page soon for another style of LED readout from the AMT 486.

AMT 486 Readout Jumper Settings + Power Switch Light Wiring for various lighting effects
http://creepingnet.hotlightbulb.com/technical/powerledreadout.html

I picked up another case with one of those readouts in it, a Desktop chassis from around 1997 or so that had a Pentium 200 MMX in it, looks like the perfect candidate for a 486 DX4 box. Also, it's MHz display looks close to yours from the back, so it might use the same settings.

TandyMan100
August 20th, 2009, 05:29 AM
For the ultimate idea of LED MHz display there is the IBM PS/2 Model 95 (the larger case Server 500 and Server 720 have the same or better capabilities too): http://www.youtube.com/watch?v=WqxRBAbbCzs&NR=1

There has even been a driver written to display specific data or design a marquee-style display...
That's pretty epic. How is it attached internally?

Chuck(G)
August 20th, 2009, 08:50 AM
I just set the 7-segment displays to show "HI" and "LO", rather than any specific (and meaningless) numeric value.

per
August 20th, 2009, 09:40 AM
I just set the 7-segment displays to show "HI" and "LO", rather than any specific (and meaningless) numeric value.

I also got one like this in my 486, however, it is covered by a plastic shield (together with the speaker and some other logics) so I can't easily reach it.

aitotat
September 9th, 2010, 10:03 AM
Does anyone have jumper instructions for MHz display on below picture?

http://kotisivu.dnainternet.net/ttilli/Components/Images/Temp/MHz_Display_Jumpers.jpg

That wire coming from turbo led was disconnected. The display probably takes power from it but I don't even know where it should be connected.

I found some MHz display instructions but nothing for display like that. Front panel of the case looks like this (http://kotisivu.dnainternet.net/ttilli/Components/Images/Temp/Pomi_Front.jpg).

per
September 9th, 2010, 10:41 AM
It can be anywhere on the lower grey box in the ilustration below; I would say the three rigthmost because those are "cleanest" (the others seems to have more dust on them).

MikeS
September 9th, 2010, 10:53 AM
It can be anywhere on the lower grey box in the ilustration below; I would say the three rigthmost because those are "cleanest" (the others seems to have more dust on them).Just curious: what'd you use to make that nice drawing?

BTW, I've got 5 or 6 layouts but none matches this one, alas.

per
September 9th, 2010, 11:04 AM
Just curious: what'd you use to make that nice drawing?

BTW, I've got 5 or 6 layouts but none matches this one, alas.

Actually, I made it in MS Paint. I just made some basic T-forms, then copy/paste-puzzeled those together the only way I could see them fit according to the jumpers. Then I applied the jumpers, and last I added the fields that remained (in grey).

Raven
September 9th, 2010, 12:08 PM
Ya can't do much harm to displays like that, I just (with power on) mess with them to see what does what and eventually get the right idea of how they work.

One of my machines had the original instruction sheet for the LED display wedged between the case front panel and the case itself, so it was still in there when I opened it up to mess with the LEDs. This model was a "T-398". If anybody needs that I can scan it for ya.

aitotat
September 11th, 2010, 07:21 AM
Based on Pers picture, I tried to connect the wire coming from turbo button to the gray area at the bottom using all possible combinations. Nothing appeared on the display so it must require power. I checked with multimeter that the resistor was connected to the rightmost pin at the bottom row. Does this mean that the bottom row should be something like this (X means segment jumper, T means turbo button, + means voltage and G means ground):
XXX TTT +G

Do you think that is correct? I don't want to take unnecessary risks.

Chuck(G)
September 11th, 2010, 08:19 AM
I looked at a few of the turbo displays that I had--some are really obscure with pins numbered only 1234... Others had the power marked as yours. "+" is most likely power and "G" is mostly likely ground. If you're in doubt, use a 100 ohm resistor in series with the +5 lead to these to make sure that everything lights up without blowing any LEDs. Remove the resistor when you're certain.

The turbo button usually goes to the motherboard, not to the display. The resistor is likely intended to be in series with the turbo LED. Once you've identified power and turbo LED leads, you can try grounding other pins to see if that changes the display.

What I'd do anyhow.

aitotat
September 11th, 2010, 09:41 AM
I tried it and + and G must be reversed. So the bottom row is actually this:
XXX TTT G+

There are two wires coming from turbo button. The other goes to the motherboard and the other goes to the display. The display was jumpered to show 8 when turbo is disabled and 50 when turbo is enabled. I'll try to figure the segment jumpers using the map per made. I'll let you all know the completed map when I'm done.

aitotat
September 11th, 2010, 10:58 PM
Here it is. Thanks to everybody and especially to per. That picture made things a lot easier.

papa_november
March 13th, 2016, 05:17 PM
Ya can't do much harm to displays like that, I just (with power on) mess with them to see what does what and eventually get the right idea of how they work.

One of my machines had the original instruction sheet for the LED display wedged between the case front panel and the case itself, so it was still in there when I opened it up to mess with the LEDs. This model was a "T-398". If anybody needs that I can scan it for ya.

I could use a scan of that. It's one of the few that have three digits and I can't make heads or tails of mine.

modem7
March 13th, 2016, 06:16 PM
This model was a "T-398". If anybody needs that I can scan it for ya.

I could use a scan of that. It's one of the few that have three digits and I can't make heads or tails of mine.
And I can add the T-398 scan to the collection at [here (http://www.minuszerodegrees.net/led_speed_display/led_speed_display.htm)].

If you provide a (decent) photo of the jumper side of your unit, then we may be able to work out the settings.
If you know what is presently displayed for non-turbo and turbo, that will assist.

tonytonitone
July 2nd, 2016, 08:12 PM
Hey, first post Hi! Sorry if this thread is too old to be bumping, but I came across a T-398 LED display in my misc computer parts bin.
I can't seem to find anything else online about it so far. I even ran across that collection too.
I'd like to be using it for various electronic projects (ie arduino, pi, etc).

I will try to get some hi-res photos of the front/back with the current jumper settings and without jumpers on.
The camera on my phone isn't cooperating atm but I'm tryin.

Cheers,

Eqwipman
February 17th, 2017, 12:58 PM
This is a reply to all the talk about the MHZ display. i have the board with the jumpers but i don't know where the display is. i would like to know how to configure the jumpers also. because the threads here are so old, most of the links no longer work. Can't find any info on the Web on how to do this. Maybe someone here has figured it out.
36281