This build is based on the kit from BudgeTronics with the addition of:
- low-profile DIL turned pin sockets for easier replacement of chips and attachment of logic probes
(I noticed afterwards that two chips are 14-pin and not 16-pin. So I had to cut off the legs of two 16-pin sockets to make it work).
- black 40-pin ZIF socket with small pins (ARIES 40-6554-10)
- rubber pads on the underside to increase height (necessary to plug in Pluggy McPlugFace)
I've also bought a TL866II+, EPROM eraser and a few AT27C1024 for easier reprogramming.
The board worked on the first try after powering up which was quite satifying!
My Gigatron build
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Use this forum to show off your build photos. For build issues, please consult the directions in the sticky post on top instead.
Use this forum to show off your build photos. For build issues, please consult the directions in the sticky post on top instead.
My Gigatron build
Last edited by cde on 15 Sep 2020, 21:17, edited 1 time in total.
Re: My Gigatron build
I gotta say, that black PCB looks really sharp!
Re: My Gigatron build
The first picture I see of a built Budgetronic Gigatron. Thanks for sharing!
Re: My Gigatron build
Thanks Walter! By the way I just tested the Tetronis demo and the music seems really strange, much too high pitched. Then I tried Tetronis in the emulator, and heard the music as it should be. I had a look at the audio DAC with a multimeter and measures 10 KOhm for pins 2 3 4 5 but 5 KOhm for pin 6. Is this to be expected? Please have a look at the following video: https://imgur.com/a/T3ilK2p (note that by default, sound is muted).
Last edited by cde on 16 Sep 2020, 13:27, edited 1 time in total.
Re: My Gigatron build
I hope you understand, but I cannot give support on Gigatrons bought elsewhere..
Re: My Gigatron build
Right, well anyway Budgetronics messed up and they provided an incorrect part for the DAC. They have provided a 6X-1-103LF, which is a simple resistor network whereas the correct part is the 4606X-R2R-103LF. Interestingly the 4606X-R2R-103LF is pretty rare and out of stock until at least december. Instead I found a 10-pin R2R 10K network on eBay which I believe will work by cutting off the extra 4 pins (7-10).
Re: My Gigatron build
As I suspected it was indeed the DAC at fault. I desoldered the invalid part and replaced it with a resistor ladder I made based on the schematics and now the Tetronis music sounds as it should.
For reference, music with invalid DAC part: https://imgur.com/a/T3ilK2p
Gigatron with proper resistor-ladder DAC: https://imgur.com/a/YXwUHhN
(note that imgur mutes videos by default)
Here's a closeup of the ladder:
For reference, music with invalid DAC part: https://imgur.com/a/T3ilK2p
Gigatron with proper resistor-ladder DAC: https://imgur.com/a/YXwUHhN
(note that imgur mutes videos by default)
Here's a closeup of the ladder:
Re: My Gigatron build
I suspect that won't work since the last 2 pins are wired differently from the rest of the SIP. I also built one a while back out of discrete SMT resistors because I couldn't think of a better solution at that time.
- Attachments
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- Capturer2r.JPG (20.37 KiB) Viewed 8076 times
Re: My Gigatron build
Thanks, you're probably right. Anyway I have contacted Budgetronics and they have found a temporary solution for other Gigatron purchasers: they will provide a ladder based on discrete resistors (in a more compact fashion than mine), until the needed component gets back in stock.
Re: My Gigatron build
I've just tested the modified 4310R-R2R-103LF with last 4 legs cut. The last resistor is indeed a bit off (60 Ohm instead of 50), but it nonetheless sounds fine to me: https://imgur.com/a/fEG4gnS
In the video above you can also see the ladder kindly sent by Budgetronics who I thank for their quick response (it is the ladder with yellow plastic and the first pin marked by a black dot).