Whiskey wrote on 2020-04-25, 16:49:

1. Is there a up to date parts list or basket for the components needed for the RC(1?) PCB which are being sent out?
I'm in the UK so will end up using https://uk.rs-online.com/ for parts, I'll share a RS part's list code once I order for any one else in the UK/Europe.

The most recent BOM that was released for the RC-1 boards can be found attached at the bottom of this post. As far as I'm aware, there is no ready-made cart as of yet.

Whiskey wrote on 2020-04-25, 16:49:

2. Are the RC PCBs being sent out with the InterWaves pre soldered (just not the ~200 odd production boards)?

The RC-1 boards will have InterWave ICs soldered; shock__ mentioned having completed this task some time ago. The recent change is that the final boards will be shipped with the InterWave ICs included, but not soldered onto the boards.

Thanks for the low-down 640k!enough.

Component hunting is going well except for sourcing the raised audio jacks (CUI SJ1-3543N). Seem to be sold out with no intention of restocking on all the UK traders I can find.
I'm also having trouble finding a pin compatible alternative with the right height. Has anyone else found a suitable replacement?

All RC cards have been sent off 😀

@Thermalwrong: I've soldered worse QFP packages by now and adapted from using hot air to using an iron + wick ... i.e. EPM7128STC100 are quite a pain with their tiny package - less pins than an InterWave, but a considerably tighter pin-density.
See: https://i.imgur.com/gbKUGH0.jpg (dead InterWave from matze's card for scale)
I'm ok with doing those occasionally and don't mind it too much, but doing 200 InterWaves is definitely not my definition of fun.

@Whiskey: can confirm the jacks are a pain to obtain. I've managed to get 20 from a local dealer, but they've run out of stock since then. Lowered jacks would also work but aren't compatible with salvaged ISA backplates I'm afraid.

If someone who never tried before thinks about soldering it themselves, I've tried a similar package with the tvga9000i just recently: Even a cheaper (~48€) hot air station from Ebay did the job quite well, if: you have good and fresh solderpaste and don't overdue on it. Airflow doesn't need to be high either. I've even desoldered and resoldered (for testing and with lots of flux) and everything survived. A steady hand (and some needle headed plastic device) while positioning and magnifying glasses might help, but considering the time it would take to solder 144 through-hole pins, this is still always faster even without and taking your time to fully be happy with the positioning.

Recently, I also found that Digikey does offer stencils for this package and I have already received one - waiting to be tested on a new build. 😀

I just use drag method with decent amount of flux between pins and a ball of solder on the tip when hand soldering a QFP and once I'm all done I use wick to get rid of the few solder bridges at the end. Dried up flux residue I scrape away and then use qtip soaked in acetone or some cleaning alcohol to remove the rest. It takes only minutes to do a chip with any amount of pins or pitch of them.

Basically what Tiido said. I'm in the very lucky position to still have very good eyes so I barely need to use a magnifying glass. If I manage to get a decent ancor point to rest my hand/fingers on on the board I usually align chips using my fingers (freehand I have a slight tremor/shaky hands that get in the way)

I think I've found a suitable substitute for the audio jack, It's the same model with out the N suffix (CUI SJ1-3543) just has a threaded barrel and nut but apart from that is identical.

Also I need some advice on the EEPROM chip; the AT93C66SC is just not available, but there are other chips which seem functionally the same such as CAT93C66VI-GT3 any advice on this would be great.

As for the other IC's these are the equivalents that I've found so far:
74F373DW > SN74F373DW
74F32D > SN74F32DR
TL082C > TL082CPSR
7805 (1A or 3A) > LM7805CT/NOPB (5V Reg)
7905 (1A) > LM7905CT/NOPB (Neg Vltg)
24.576MHz Crystal > 9B-24.576MEEJ-B (30ppm 18pF)
6.9344MHz Crystal > AS-16.9344MAHH-B (30ppm 15pF)

I found Everything else is available and easy to find. I used https://uk.rs-online.com/ for the SMD parts, https://www.mouser.co.uk/ for the common ICs and https://uk.utsource.net/ for the DRAM and MS6308.
Already have a supply of IW78C21M1 chips I bought in 2018.

Whiskey wrote on 2020-04-26, 15:11:

Also I need some advice on the EEPROM chip; the AT93C66SC is just not available, but there are other chips which seem functionally the same such as CAT93C66VI-GT3 any advice on this would be great.

Would you mind creating and sharing a Mouse/RS/Digikey project, so that others don't have to do the searching? I don't get a card (would love to have one of course), but it might ease the process for other people.

Substituting AT93C66SC with CAT93C66VI-GT3 should work.
As for the MS6308, there's some replacement type which I successfully tested, I'll make sure to let you know what it's called when I get back home from work.
EDIT: TDA1308 from NXP is a substitute for the MS6308

This is great news, I'd rather not use utsource if I can avoid it as the postage is insane right now. EDIT: alas TDA1308 is also hard to come by but would OPA1692 be suitable?

Any ideas on a swap out replacement for the DRAM chips HY514260BJC-60 or HY5118160JC-70? As I can only find these available for quantities over 1000 units on UTS.

Basically all 256k*16 or 1MB*16 DRAMs in a suitable package should work, speed shouldn't be slower than 70ns (80ns might still work but is unconfirmed).
I salvaged mine from old EDO RAM sticks (1MB*16 types) or VGA cards (256k*16 types).

shock__ wrote on 2020-04-27, 11:39:

speed shouldn't be slower than 70ns (80ns might still work but is unconfirmed).

The Gravis manual originally stated 80 ns or faster, but they also included a yellow notice in the packaging that corrected that to 70 ns or faster. It stands to reason that 80 ns appears to work most of the time, but can produce occasional problems, much like we had with the 90 ns flash trials.

@shock__

PCB arrived, thankyou so much! Looking forward to assembling it 😀

Thanks for repairing my Prototype Card, it works fine now!

So this is considered to start off again ? i was expecting its stalled forever 😀
maybe i pull out my opl2 addon files again.

I'm determined to finish this project this year so I can be done with it and people can enjoy their cards.
With the first cards arriving now, I'll set a 3 months testing period til the end of July 2020.
Plan is to order and ship the final design in August.

shock__ wrote on 2020-05-05, 11:38:

I'm determined to finish this project this year so I can be done with it and people can enjoy their cards.
With the first cards arriving now, I'll set a 3 months testing period til the end of July 2020.
Plan is to order and ship the final design in August.

If anyone jumps off the list, I will be glad to take their place. 😉

root42 wrote on 2020-05-05, 13:25:

If anyone jumps off the list, I will be glad to take their place. 😉

Wish someone could offer that - we'd probably get an extensive teaser video out of it 😁

This is the most "teaser" like you'll get for a while.
https://www.youtube.com/watch?v=uQwjjuAjmz8

Once the initial run is over, I might be able to deliver a few more, as I have an excess of InterWave chips and the PCB design can be replicated as many times as desired. But no definite plans there yet.

shock__ wrote on 2020-05-06, 14:59:

This is the most "teaser" like you'll get for a while.
https://www.youtube.com/watch?v=uQwjjuAjmz8

Once the initial run is over, I might be able to deliver a few more, as I have an excess of InterWave chips and the PCB design can be replicated as many times as desired. But no definite plans there yet.

I hope I can get in on that batch.

What's the degree of interest?
Me: Yes.