NeXT Computers Forum Index NeXT Computers
www.NeXTComputers.org
 
Log in to check your private messagesLog in to check your private messages

Log inLog in  RegisterRegister


Profile  Search  Memberlist  FAQ  Usergroups
NeXT ADB soundboard to NON ADB conversion?
Goto page Previous  1, 2, 3, 4, 5, 6  Next
 
Post new topic   Reply to topic    NeXT Computers Forum Index -> NeXT Work Logs
View previous topic :: View next topic  
Author Message
barcher174



Joined: 07 Dec 2012
Posts: 558

PostPosted: Sun Oct 04, 2015 10:00 pm    Post subject: Reply with quote

I added info on creating a dummy load to my instructions:

http://asterontech.com/Asterontech/next_adb_conversion.html

It's simple enough. Just use 2, 5w 68ohm resistors in parallel, and embed them in a heat sink so they don't disturb the other components. You will need to find a smaller speaker for everything to fit. I'm using laptop speakers and it works great. Just use 8ohm, 1 watt speakers. Now the soundbox is truly universal and can be used on any black hardware.

--
Brian
Back to top
View user's profile Send private message
paolo.bertolo



Joined: 24 Sep 2015
Posts: 57
Location: St Gallen, Switzerland

PostPosted: Sun Dec 13, 2015 12:11 pm    Post subject: Reply with quote

Hello Everyone,

I would like to share this ADB sound card mod Iíve made following the instructions available on the forum thanks to the work of barcher174 (thanks to him for the kind and prompt feedback to my requests).

Iíve stripped down and re-capped an ADB sound card and made an adapter for both a VGA display or a Macintosh one.

Yes, surprisingly enough, my Apple Multiple Scan 17Ē Display can work perfectly fine even though on the paper is does not accept the fancy resolution of the NeXT. Just tried and worked fine after some little manual adjustment, so Iíve made a parallel output.

Tested with my NeXTstation mono, Iím planning to add a switch and an array of power resistors as dummy load for making it compatible with my Cube 030.

Stripped down and re-capped board

https://dl.dropboxusercontent.com/u/47587908/stripped%20down%20and%20recapped%20board.jpg

Final

https://dl.dropboxusercontent.com/u/47587908/final.jpg

Eizo L768

https://dl.dropboxusercontent.com/u/47587908/Eizo%20L768.jpg

Apple Multiple Scan 17

https://dl.dropboxusercontent.com/u/47587908/Apple%20Multiple%20Scan%2017.jpg[/img]
Back to top
View user's profile Send private message
barcher174



Joined: 07 Dec 2012
Posts: 558

PostPosted: Sun Dec 13, 2015 2:36 pm    Post subject: Reply with quote

Very nice work! I like the project box you used. Where did you get it? Also I should mention that the large electrolytic capacitor is only needed if you have the internal speaker hooked up. I notice that you removed that header entirely. Not sure if you had any clearance issues with that.

Thanks,
Brian
Back to top
View user's profile Send private message
paolo.bertolo



Joined: 24 Sep 2015
Posts: 57
Location: St Gallen, Switzerland

PostPosted: Sun Dec 13, 2015 3:20 pm    Post subject: Reply with quote

Thanks Brian!
The box is a Takachi PF15-3-10, I got it via Farnell. I've spent some time trying to find a good match, I would have preferred something in aluminium but eventually opted for this one, since ABS is much easier to cut than Al (I don't have a dremel, I've only used a knife and sandpaper).
Actually, the trickiest part was to hack the box and the board to get everything mounted in a robust and solid way.
I must admit that the execution is not one of the finest ever, I had to make some compromises, still is fully functional and that for the moment was my sole purpose.
As for the big capacitor, I've replaced it with a more compact one, which is now mounted flat.
However, as you could see, for the moment I've removed the jack for the external speaker and used one of the empty mounting holes for securing the board to the bottom of the box with a screw (I'm using two of them).
I would like to further improve the box by having some Al front and rear panel for a more elegant mounting of the connectors, plus restoring the external audio jack and adding an "expansion" connector for the power resistors (still have no idea about how to make it, though, but I think they definitely need to be outside the box to keep inside temperature under control).
Back to top
View user's profile Send private message
Stefano



Joined: 29 May 2014
Posts: 8

PostPosted: Fri Jan 15, 2016 9:24 am    Post subject: Reply with quote

Wonderful job Paolo!

Bought the kit from Rob Blessin and I'm planning modding my ADB sound PCB this weekend... I've been postponing this for a year, hehe.

I've got a simple plastic project box, but it's ugly.
http://www.patola.com.br/index.php?route=product/product&path=59_68&product_id=89
Back to top
View user's profile Send private message
paolo.bertolo



Joined: 24 Sep 2015
Posts: 57
Location: St Gallen, Switzerland

PostPosted: Sat Jan 30, 2016 11:59 am    Post subject: Reply with quote

Ciao Stefano,

thanks for your lines. I'm actually stuck with this small project, I've looked around for some Al case but they are all way more expensive than what I'm targeting at.
I guess I will try to integrate the plastic case from Takachi with some 3D printed side walls designed around the connectors in order to give them a neat and precise arrangement.
As for the power resistors for the Cube 030, I was thinking about adding this load externally, but I still have to figure out how...
If you have some ideas, they are all more than welcome!
Back to top
View user's profile Send private message
paolo.bertolo



Joined: 24 Sep 2015
Posts: 57
Location: St Gallen, Switzerland

PostPosted: Sun Apr 17, 2016 9:58 am    Post subject: Reply with quote

Quick update, just to add extra confirmation (needed?) about Brian's great set of instructions.

In order to use the adapted ADB board with my 030 Cube with rev 152 power supply, I've tested the suggested dummy load (30 Ohm, draining ~400mA on the -12V line).

So, I've connected in parallel 5 spare resistors (150 Ohm, 1W max). At 12 V, they work close to the max power (0.96 W), and obviously they get pretty hot. But as long as they are free to breath (I have them hanging out of the small box) and you don't touch them, it should be fine for occasional and short runs. Not very elegant, but effective.

Tested on the Cube and on the Mono Station, works on both.

Array of resistors

https://dl.dropboxusercontent.com/u/47587908/IMG_0158.JPG

Cube + Eizo L768

https://dl.dropboxusercontent.com/u/47587908/IMG_0159.JPG
Back to top
View user's profile Send private message
paolo.bertolo



Joined: 24 Sep 2015
Posts: 57
Location: St Gallen, Switzerland

PostPosted: Sun May 22, 2016 1:18 am    Post subject: Reply with quote

Hi All,
just wanted to share about yet another legacy display which works great with black hardware (supports SOG) and also offers a very nice color match: Eizo FlexScan S1910 (black).
Back to top
View user's profile Send private message
Rob Blessin Black Hole
Site Admin


Joined: 05 Sep 2006
Posts: 597
Location: Ft. Collins, Colorado

PostPosted: Fri Jan 13, 2017 10:30 pm    Post subject: Reply with quote

Hello: VERY IMPORTANT TO READ BRIANS RESPONSE 😀!

We have been modifying lots of NeXT ADB Boards to be dual compatible
for both ADB and NON ADB Components but I'm having a problem with sound working from the legacy NeXT speaker on the majority of boards.
The boards have new capacitors from Charles at MacCaps.
Matt is doing the Non ADB to ADB Conversion and he does nice work with years of experience at Celestica Motherboards.
So it should be easy to trace the following problem that is cropping up and prevent or fix it for future conversions ,
we are all basically inventing the adb to non adb conversion using what we have available riding the coattails of Brian Archer our guru and it is fun,

So has anyone else had this happen where the asic chip pictured below pops after doing the conversion?

As we are finding out that something in the configuration is smoking an ASIC Chip on some boards but not others.

My guess is it is being caused by the wrong resistor or a short ?

Here are 4 examples , recommend mounting the NON ADB keyboard on right side looking in as annotated

However there is no sound on 3 of the 4 boards unless we plug in powered speakers but 3 of them may just have blown asic chips.

What are we doing something wrong?

The Microphone works and powered external speakers even on boards with blown asic chips . Any help appreciated , he has started shrink wrapping the wires as well as gluing them to the surface of the chips



_________________
Rob Blessin President computerpowwow ebay sales@blackholeinc.com http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community since 2/9/93


Last edited by Rob Blessin Black Hole on Sat Jan 14, 2017 2:10 am; edited 1 time in total
Back to top
View user's profile Send private message Send e-mail Visit poster's website
barcher174



Joined: 07 Dec 2012
Posts: 558

PostPosted: Fri Jan 13, 2017 11:36 pm    Post subject: Reply with quote

The case is conductive. You need to isolate the bottom of the circuit board. What is happening is the pins below the large cap are shorting and blowing the mono amp. It's a standard part and you should be able to find replacements. It's only a matter of time before the others blow as well. I use rubber bumpons stuck to the bottom of the board.
Back to top
View user's profile Send private message
barcher174



Joined: 07 Dec 2012
Posts: 558

PostPosted: Fri Jan 13, 2017 11:47 pm    Post subject: Reply with quote

Here are replacement Mono amp ICs:

http://www.ebay.com/itm/5PCS-audio-amplifier-IC-DIP-8-TDA7052A-TDA7052A-N2-TDA7052AN-/361687879206?hash=item5436470e26:g:V5IAAOSw0UdXsZM4

Bumpons:

https://www.amazon.com/3M-SJ5302-Bumpon-Blister-Bumpons/dp/B01ACPT2LU/ref=sr_1_3?ie=UTF8&qid=1484376329&sr=8-3&keywords=bumpons

Good replacement speakers (sound fine and give plenty of clearance in the case to do whatever you want, VGA etc..):

https://www.amazon.com/gp/product/B00H8VXQ8M/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
Back to top
View user's profile Send private message
Rob Blessin Black Hole
Site Admin


Joined: 05 Sep 2006
Posts: 597
Location: Ft. Collins, Colorado

PostPosted: Sat Jan 14, 2017 1:42 am    Post subject: Reply with quote

barcher174 wrote:
The case is conductive. You need to isolate the bottom of the circuit board. What is happening is the pins below the large cap are shorting and blowing the mono amp. It's a standard part and you should be able to find replacements. It's only a matter of time before the others blow as well. I use rubber bumpons stuck to the bottom of the board.

Awesome that makes sense , did not realize the case was conductive , I'll pick up some bumpons asap or in the interim would electrical tape work as well?
Ordered all 3 items , kind of funny all these years and never tried powered speakers which are built into a dell flat panel with speaker bar and plugging into the NeXT sound card , they sound good.thanks again !
_________________
Rob Blessin President computerpowwow ebay sales@blackholeinc.com http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community since 2/9/93
Back to top
View user's profile Send private message Send e-mail Visit poster's website
barcher174



Joined: 07 Dec 2012
Posts: 558

PostPosted: Sat Jan 14, 2017 2:23 am    Post subject: Reply with quote

Yes, electrical tape would also work.
Back to top
View user's profile Send private message
Rob Blessin Black Hole
Site Admin


Joined: 05 Sep 2006
Posts: 597
Location: Ft. Collins, Colorado

PostPosted: Sun Jan 29, 2017 12:55 am    Post subject: Reply with quote

Hello Brian: To let you and everyone know we replaced the audio chips on several soundboards that had blown because of contact with the case ,
the replacement IC chip does work but the volume is really low hardley audible compared to the original NeXT IC's when run through and original NeXT speaker ,
however powered speakers work great as they not dependent on the mono amp IC. I have not tried the after market microphone and
really small speakers yet but please note they have tiny lead wires
and we will have to buy connectors with leads rather than solder them to the internal speaker connector ,
the advantage will be more room for the VGA passthrough and load boards etc , still it is all really cool and I'll keep you posted.
_________________
Rob Blessin President computerpowwow ebay sales@blackholeinc.com http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community since 2/9/93
Back to top
View user's profile Send private message Send e-mail Visit poster's website
paolo.bertolo



Joined: 24 Sep 2015
Posts: 57
Location: St Gallen, Switzerland

PostPosted: Sun Jan 29, 2017 3:09 am    Post subject: Reply with quote

Dear All,
for those who may be interested, here please find my latest (and last) take on "ADB to non ADB soundboard conversion".
The box is perfectly sized and, since it's all aluminium, it also doubles as heat sink for the power resistor (the red switch cuts it off in case it's not needed).
The second 15 pin connector can be used with Apple legacy monitors (for the moment not wired for avoiding too much cluttering).
The speaker is very small but does a decent job.
Looks a little bit like a spaghetti board, but I preferred to keep it as modular and reversible as possible.
Finally, as Brian suggests, video / hsync and vsync should run over shielded cables to keep video output quality at a decent level.




Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    NeXT Computers Forum Index -> NeXT Work Logs All times are GMT - 7 Hours
Goto page Previous  1, 2, 3, 4, 5, 6  Next
Page 5 of 6

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum



Powered by phpBB © 2017 phpBB Group