Re: Replicas of Covox Speech Thing, FTL Sound Adapter and SiliconSoft SoundJr

Posted on 2019-04-07, 18:58

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

I have added an additional resistor pack to the FTL Sound Adapter replica for short circuit prevention. FTL_Sound_Adapter_replica_3d.png Without these additional resistors that are connected in series with the control lines, using the joystick port could potentially damage CMOS-based parallel ports. …

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Re: Where do I find SMC for repair?

Posted on 2019-04-07, 08:50

by

by Benedikt

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Please also note that quartz crystal resonators are very sensitive to mechanical shock, more than anything else on that board. If the quartz wafer in that metal capsule has shattered, the GPU does not get any clock signal and will therefore seem to be dead, even when perfectly intact.

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Re: TANDY Dos-Gaming-Thread (1000RL/HD)

Posted on 2019-04-05, 16:33

by

by Benedikt

in Marvin \ Software

in Marvin \ Software

I put this VGA/MCGA mode 13h emulation TSR driver for Tandy Video II on github, today. It also does some sanity checks, now, can be unloaded and can fool basic int 10h based MCGA detection.

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Re: TANDY Dos-Gaming-Thread (1000RL/HD)

Posted on 2019-04-01, 10:58

by

by Benedikt

in Marvin \ Software

in Marvin \ Software

I do not have a demo video, right now, but I do have screenshots (DosBox) of a simple demo: fire_13h.png fire_13h_tsr_on_tandy_640x200x16.png This is unfortunately also a demo of the limitations, because the code relies on the exact values in video RAM and the pixel data therefore cannot be …

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Re: TANDY Dos-Gaming-Thread (1000RL/HD)

Posted on 2019-03-31, 19:56

by

by Benedikt

in Marvin \ Software

in Marvin \ Software

Regarding the 640x200x16 mode: I'm currently fiddling around with some TSR code that pretends to set VGA's 320x200x256 mode 13h while actually setting the Tandy mode. Since that mode has a compatible memory layout, every 256 color pixel will simply show up as a pair of 16 color pixels. Viewed from a …

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Re: Tube Time: Announcing The Snark Barker, a 100% Compatible SB 1.0 Replica!

Posted on 2019-03-28, 22:15

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

Almost the right one" http://www.bracket.com/downloads/brackets/pdf/93590001B.pdf Huh, did not find that one, I did not do the search for 3 rond holes. It's dated 1993, So it's probably another ISA sound card. Really cool they have it all available online. On a similar note: Would it be possible to …

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Re: What to do with original sound card box? (dirty - possible animal urin)

Posted on 2019-03-28, 13:19

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

If it smells like pee, I'd scan it and ditch it, indeed. Even if it were in otherwise pristine condition, I'd only want to see it in an air-tight glass cabinet in a museum.

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Re: PC Speaker with Soundcards that Don't Have Headers

Posted on 2019-03-26, 11:07

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

I have not tried anything like that, but the approach should work, provided that the soundcard's internal mixer can route the input straight through to the output and provided that the levels are compatible. Since the PC Speaker header is designed to drive a speaker, some attenuation might be …

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Re: Replicas of Covox Speech Thing, FTL Sound Adapter and SiliconSoft SoundJr

Posted on 2019-03-21, 17:50

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

Given that there is no discreet amp, as had been thought, that action is accomplished by the transistors, correct? Correct. One thing I'm curious about, do you see anything that would support the supposition that for some reason it wouldn't work on a given parallel port, compared to a Speech Thing? …

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Re: Covox Sound Master Reverse Engineering / Replica

Posted on 2019-03-21, 17:11

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

matze79 wrote: Who cares about Keystone. I don't care whether it's by Keystone, just whether it fits. And, comparing the layout to the data sheet, I can now say that it doesn't. So that's off the table.

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Re: Covox Sound Master Reverse Engineering / Replica

Posted on 2019-03-21, 09:15

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

Speaking of which: What are the odds that the Keystone 9200-15 bracket fits? It might not, but if it does, that would reduce the effort to drilling a hole for the audio jack.

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Re: Covox Sound Master Reverse Engineering / Replica

Posted on 2019-03-21, 08:33

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

Mmh... are the optional load resistor and the 10kΩ resistor above it connected in parallel? If so (I cannot see through the board), you could simply install a 7.15kΩ resistor from the E96 series instead of the 10kΩ one and scrap the additional footprint.

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Re: Covox Sound Master Reverse Engineering / Replica

Posted on 2019-03-20, 20:43

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

Nice! That adds a bit more flexibility. The 2% tolerance should not be a problem, because they apply to the resistor network as a whole. The resistors within should be closely matched. Also, the 4310R-R2R-104(LF) and 4610X-R2R-104(LF) are interchangeable, which means that only one of them has to be …

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Re: Replicas of Covox Speech Thing, FTL Sound Adapter and SiliconSoft SoundJr

Posted on 2019-03-20, 14:23

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

Alright! This is the (hopefully) complete schematic of the SoundJr: Filename SoundJr_schematic_messy.png File size 26.64 KiB Views 1768 views File comment SoundJr schematic – untested, with components all over the place At this point, I'm not quite sure how it does volume control. It does not …

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Re: Replicas of Covox Speech Thing, FTL Sound Adapter and SiliconSoft SoundJr

Posted on 2019-03-20, 08:37

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

My basic theory has not changed. Apparently, the NPN transistors pull the additional DAC lines to GND, while the PNP transistors pull them to VCC. The design uses 20kΩ base resistors, as well. The presence of these NPN transistors and base resistors does indeed make perfect sense. EDIT: They might …

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Re: Replicas of Covox Speech Thing, FTL Sound Adapter and SiliconSoft SoundJr

Posted on 2019-03-19, 20:38

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

Thank you, Cloudschatze! That back side is a bit more crowded than I expected. I see: The expected 8×10kΩ resistor array Four more 10kΩ resistors Three more 20kΩ resistors Two capacitors (filtering?) A 470Ω resistor Another 100Ω resistor Another PNP transistor Four NPN transistors (MMST2222A) And …

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Re: Covox Sound Master Reverse Engineering / Replica

Posted on 2019-03-19, 10:32

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

Are you sure that R is 200kΩ, or might that be 2R? EDIT: Never mind. You are sure that it's 2R. And yes, the 4310R-R2R-104LF is a 100kΩ part. I'm asking because the Speech Thing uses a resistor network where 2R is 200kΩ, R is 100kΩ and the load resistor 25.5kΩ. It would have made sense for Covox to …

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Re: Replicas of Covox Speech Thing, FTL Sound Adapter and SiliconSoft SoundJr

Posted on 2019-03-19, 10:15

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

I can wait. (I.e. won't be ordering any parts for at least a couple of weeks, anyway.)

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Re: Covox Sound Master Reverse Engineering / Replica

Posted on 2019-03-19, 09:46

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

As I was afraid it is not a regular bus network. This network has R-2R ladder inside and can not be easily found online for a reasonable price. :dead: Would it be possible to somehow bodge-solder a Bourns 4310R-R2R-104LF in there? That part is very similar to the one in the Covox Speech Thing but …

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Re: New Analog Input Card / Game Contol Adapter to supplement your Adlib

Posted on 2019-03-17, 16:04

by

by Benedikt

in Marvin \ Sound

in Marvin \ Sound

matze79 wrote: Who cares about FTL Soundadapter Gameport, it works with nothing. Except Dungeon Master, so its just a Piece of Junk. Patching the keyboard interrupt via TSR driver should do the trick. A "mouse" driver would also be an option.

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