15 replies to this topic

[Tator]

Hi,
     I built an HdX PCB to modify an RS232, Fred Kaal design, (http://members.ziggo...kaal/index.html)
and now I´m ready to mount it in the original RS232 but have some doubts regarding the installations of the switchs and would like to check if somebody already did it and can help me.

1) According to the schematic view (http://members.ziggo...232_dsr_ram.gif) the trace that has to be cutted is the one that goes from pin 8 of the 74LS21 (u17) to pin 1 of the 74LS125 (u6), but in the picture of the modifier RS232 card (http://members.ziggo...card_rs232.html) the trace that is cutted is pin #3 of the 74LS125 (u6).

2) Switch 1 (SW1) is added to be able to close the previous cutted trace and also pin #1 of the 74LS125 (u6) is connected with a 10K Resistance (R6)  to +5V, is that correct? Any suggestion on where to take those +5V? Could pin12/13 of the 74LS21 (u17) be used?

I´ll appreciate your help!

Kind regards

Sebastian Magnasco

Attached Files

•  ti99_rs232_dsr_ram.gif   45.76K   25 downloads
•  ti99-rs232-complete.gif   1.34MB   27 downloads

[retroclouds]

Hi Sebastian, quick question; Have you tried to contact Fred Kaal via email ?
He's not on this forum, but he can be contacted via email.

[Willsy]

I have an HDX card that was built by Fred. I can take a look at what he did.

[Tator]

Thank you for your answers, I don´t have Fred Kaal email, does anybody knows in which email I can contact him?

Thank you

Sebastian

[retroclouds]

PM sent.

[arcadeshopper]

I just built one as well. Had zero problems getting it running.

https://sphotos-b.xx...411104870_n.jpg
is my board with the hacky wiring

You can see i just cut the lead of the chip where the interrupt is off the board and bent it up and attached a wire to it and the the other side of the switch is just wired to the test point on that same trace down near the peb connector (because I'm lazy and soldered it to the easier spot

The other three wires were soldered to chips and the other test point per his instructions at http://members.ziggo...32-complete.gif And the resistor removed at R19..

Greg

 Tator, on Mon Jan 7, 2013 1:12 PM, said:

Hi,
I built an HdX PCB to modify an RS232, Fred Kaal design, (http://members.ziggo...kaal/index.html)
and now I´m ready to mount it in the original RS232 but have some doubts regarding the installations of the switchs and would like to check if somebody already did it and can help me.

1) According to the schematic view (http://members.ziggo...232_dsr_ram.gif) the trace that has to be cutted is the one that goes from pin 8 of the 74LS21 (u17) to pin 1 of the 74LS125 (u6), but in the picture of the modifier RS232 card (http://members.ziggo...card_rs232.html) the trace that is cutted is pin #3 of the 74LS125 (u6).

2) Switch 1 (SW1) is added to be able to close the previous cutted trace and also pin #1 of the 74LS125 (u6) is connected with a 10K Resistance (R6)  to +5V, is that correct? Any suggestion on where to take those +5V? Could pin12/13 of the 74LS21 (u17) be used?

I´ll appreciate your help!

Kind regards

Sebastian Magnasco

Edited by arcadeshopper, Mon Feb 11, 2013 4:38 PM.

[CantStopClicking]

 retroclouds, on Wed Jan 9, 2013 11:52 AM, said:

PM sent.

Could you share the photos of your board?  This is one of my next projects.  I'd love to see another working example.

Thanks in advance!

[Tator]

Of course, I´m attaching the pics, aswell as some tips based on my learnings building the project that may help you.

- Please note that Fred updated the schematics to include with or without switch option.

- I did a PCB, but if you are not familiar with doing this or can´t get one done I would recommend  to
use a standard perforated project board. Drilling the holes at the precise location for the IC socket and the connector is not very easy. .

- I kept half of the original metallic clamshell and just added a couple of nuts and washers to the original nuts to still have it as a heat disipator. ( see pics)

- I couldn´t find small switches that can fit nicely in the card so I decided for a jumper-type solution using a pair of onboard male plug connectors. ( see pics).

Hope this helps.

Any doubt, just let me know.

Best

Sebastian

Attached Files

•  tn_DSC00433.JPG   72.85K   26 downloads
•  tn_DSC00435.JPG   111.11K   35 downloads
•  tn_DSC00436.JPG   72.98K   36 downloads
•  tn_DSC00437.JPG   82.26K   35 downloads
•  tn_DSC00438.JPG   38.42K   34 downloads
•  tn_DSC00439.JPG   65.35K   35 downloads
•  tn_DSC00440.JPG   67.43K   36 downloads
•  tn_DSC00442.JPG   60K   37 downloads
•  tn_DSC00443.JPG   141.59K   37 downloads
•  tn_DSC00444.JPG   102.92K   29 downloads

[Stuart]

A Maxim DS1210 (http://datasheets.ma...n/ds/DS1210.pdf) would make a good replacement for all those diodes, transistors and resistors in providing backup power for the RAM. It's a pretty foolproof little 8-pin chip that I've used with no problems in the past.  

[CantStopClicking]

Tator: Sweet!  Thanks for posting the pic's and sharing your comments.

Stuart: That's a cool little package there (DS1210).  I could see that getting implemented in a SuperCART.    I just wish I knew enough to engineer something with it!

Is there any interest in a group buy on a PCB order for the HDX project?  And probably more important, is there any cost benefit in a group buy?

If so, I'd be happy to get the ball rolling.

[arcadeshopper]

Note, Fred released a DSR and HDX pc side update today. http://members.ziggo...dx.html#ti99hdx the new server is not compatible with the old DSR so you should update the DSR first.

I am already ordering a small run of boards if they are good quality-wise/work right  I plan on a pre-order group buy for more.  

Greg

 CantStopClicking, on Thu Jan 31, 2013 3:06 AM, said:

Tator: Sweet!  Thanks for posting the pic's and sharing your comments.

Stuart: That's a cool little package there (DS1210).  I could see that getting implemented in a SuperCART.    I just wish I knew enough to engineer something with it!

Is there any interest in a group buy on a PCB order for the HDX project?  And probably more important, is there any cost benefit in a group buy?

If so, I'd be happy to get the ball rolling.

[CantStopClicking]

 arcadeshopper, on Mon Feb 11, 2013 4:11 PM, said:

Note, Fred released a DSR and HDX pc side update today. http://members.ziggo...dx.html#ti99hdx the new server is not compatible with the old DSR so you should update the DSR first.

I am already ordering a small run of boards if they are good quality-wise/work right  I plan on a pre-order group buy for more.  

Greg

Definitely count me in!  As "they" say.... +1

-Dano

[arcadeshopper]

 CantStopClicking, on Mon Feb 11, 2013 5:08 PM, said:

Definitely count me in!  As "they" say.... +1

-Dano

I got in my small run of boards and just built one last night,  works great.  Anyone else interested lmk and I'll add you to the count for the next order. Dano's already on it

Greg

[CantStopClicking]

Dano is super happy!

[arcadeshopper]

 arcadeshopper, on Thu Feb 28, 2013 4:27 PM, said:

I got in my small run of boards and just built one last night,  works great.  Anyone else interested lmk and I'll add you to the count for the next order. Dano's already on it

Greg

http://www.arcadesho...id=21147033  is the pre-order for the next run of boards.  There's a google wallet checkout link in the cart for cards.

Edited by arcadeshopper, Mon Mar 11, 2013 10:53 AM.

[arcadeshopper]

 arcadeshopper, on Mon Mar 11, 2013 10:52 AM, said:

http://www.arcadesho...id=21147033  is the pre-order for the next run of boards.  There's a google wallet checkout link in the cart for cards.

Pre-order is now closed.. will be ordering the boards tomorrow 3/22 eta is 3-4 weeks

Greg