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DEC RX02 Emulator - AK6DN

OmniSystems

OmniSystems

New Member
Joined
Apr 8, 2022
Messages
9
Location
Sparta, NJ
Has anyone run a batch of the PCB for this RX02 emulator? I would like to try and assemble one, but seems silly to run a batch of boards to just get a couple - maybe someone has already had some made and could share one or two? Or would be interested in putting together an order for 10 or 20 pieces?
 
I recently built five of these (minimum PCB order from the supplier). Since there were so few parts I loaded all five boards. One of them is already committed to someone.
Have started to test it with an M8357R but have been distracted recently by other really fun PDP-8 things. I did write a simple Arduino hardware test though, to verify the signals on the flat-cable, and LEDs.

Are you looking to use it with a PDP-8? or PDP-11? Have a controller board?
 
I still have a number of the bare emulator PCB fabs available; they are US$10 each. SparkFun microSD breakout/adapter boards are available for US$5 each (and are also available direct from SparkFun). Also a kit of all discrete parts needed; cost is US$15. So US$30 for the whole set, just supply your own ArduinoMega2560, a MicroSD card for data storage (a small 4GB one is more that enough storage) and of course you need an interface board for your system (RX8E/28, RX11/211, RXV11/21). Shipping is extra. Send me a PM if interested in a purchase.

As of 08-Apr-2022:
I still have 8 of the RX02_EMULATOR full kits available. Just assemble and add your own Arduino Mega2560 and microSD card.
In addition I have 18 bare PCB fabs left and the same number of microSD adapters. Add your own discrete parts.
 
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Sparkfun recently had an issue with their microSD adapters. I ordered mine on Feb 3rd. The adapters I received had the wrong type of socket installed on the board when the board was manufactured. The result was that the card detect pin, CD, was permanently shorted to GND. I contacted Sparkfun to let them know about the issue and they graciously sent me a refund. Not sure if Sparkfun has had the opportunity to get new boards from the manufacturer with the proper socket. I think getting the full kit from Don is probably the best thing to do.

If anyone has one of the incorrectly built MicroSD adapters and is interested, let me know and I can post a photo showing how to rework it, but the result is that CD in inverted. Consequently, I inverted CD in my personal version of the RX02 Emulator Arduino software.
 
I bought a bunch of microSD adapters in bulk (like 25pcs) several years ago from SparkFun.
Have had no issues with those. Have 20+ still left, along with 18 bare fabs. Only 5 full kits left at this point.
 
I have every one of the controllers ... RX28, RX211, RXV21 and PDP8A, 8E, 11/23, 11/73 and 11/34 systems to run them on, although none of them has been turned on or used for several years now. I once had a BA11VA (shoebox 11 chassis) with an 11/73 system that fit in just 4 slots ... I would like to recreate something similar in terms of a compact portable system. I regret having sold a 8 quad slot Q-Bus chassis that was in an aluminum enclosure (fairly light weight) several years ago.

I probably have a lot of the parts hanging around, but time is most valuable at the moment so full kits would be most desireable (and insure that I get it put together more promptly) at the moment, although one or two full kits and a couple of PCB only (for future use) is also of interest.
 
AK6DN said:
I bought a bunch of microSD adapters in bulk (like 25pcs) several years ago from SparkFun.
Have had no issues with those. Have 20+ still left, along with 18 bare fabs. Only 5 full kits left at this point.
Click to expand...
It took me a while to figure out that as a new member I can't send a direct message ... So perhaps AK6DN could message me, and then I would be able to reply?
 
OmniSystems said:
I have every one of the controllers ... RX28, RX211, RXV21 and PDP8A, 8E, 11/23, 11/73 and 11/34 systems to run them on, although none of them has been turned on or used for several years now. I once had a BA11VA (shoebox 11 chassis) with an 11/73 system that fit in just 4 slots ...
Click to expand...

Can you tell me more about this BA11VA system? I have one that I run an 11/2 processor in, but have hesitated to use 11/23 or 11/73 cards in it, since those processors, with any other cards added, take it past the 5V 5.5 A limit of the BA11VA's power supply. Did you do any mods to deal with this, or was the stock power supply good for it, even though t was loaded past its specification?
 
I was definitley running an 11/23 or 11/73 processor with 22 bit memory board, an MXV11 for serial lines, clock and boot and a Dilog DQ614 emulating RL02's.
I ran TSX11 on it ... multi-user RT11, I do not recall doing any kind of mods, and did not have any issues?
I think that some of the specs are "worst case" and that for regular run operations it got by ok I do not recall any crashes, intermittents or other issues.
 
OmniSystems said:
I was definitley running an 11/23 or 11/73 processor with 22 bit memory board, an MXV11 for serial lines, clock and boot and a Dilog DQ614 emulating RL02's.
I ran TSX11 on it ... multi-user RT11, I do not recall doing any kind of mods, and did not have any issues?
I think that some of the specs are "worst case" and that for regular run operations it got by ok I do not recall any crashes, intermittents or other issues.
Click to expand...
Thanks for the info.
 
Nothing definite here, just thought I'd fool around a bit and see about recasting the RX02 emulator shield from thru-hole to SMT.
Then when (if) I get boards made I would get them fully assembled at the same time with all components.
Still haven't done anything about the Arduino headers (left as thru hole for now). Investigating possible SMT solution to make a fully no-soldering required design.
Would require double sided SMT (which is certainly doable) but I don't have a handle on the cost, etc implications yet.

Thoughts and feedback appreciated. Note this was a bored afternoon project, no guarantee it will ever go anywhere. I still have thru-hole boards left LOL.

rx02_emulator_v5_smt.jpg
 
I'm not a fan of surface mount connectors, in particular when they are subjected to mechanical stress (broken solder joints). The Arduino connectors would probably be okay, but the ribbon connectors could be an issue unless they were suitably strain relieved.

CW
 
m_thompson said:
It might be more convenient if the MicroSD socket was at the edge of the PCB. You could print a case and change the SD card from the outside.
Click to expand...
Yeah, I did that in the older version where the SparkFun microSD adapter board would fly over the big arduino connector on the right.
I guess the options would be to either (1) extend the width of the board about 1inch, and move the microSD socket to the right of the arduino connector, or
(2) move the microSD socket to the left side, over where the USB and power connectors and LEDs are.
Thoughts?
 
If you are trying to optimize for SMT assembly, you can always just recreate the Arduino bits (ATMEGA2560, serial bits, VRM, crystals) as part of your design. Although with the current pricing and availability on ATMEGA2560 chips, it's way easier/cheaper just to get assembled boards. I would agree with Bitly, stick to THT for something like the IDC port. There's a reason you still see those components as THT, even on modern PC motherboards.

When I was doing the design that turned into the button/LCD variant, I originally toyed with doing a super small version using the Mega 2560 Pro Embed form factor you can get from the Chinese sellers and SMT components. Could have probably even fit a full size SD card slot on it which I find much more convenient that micro's, especially once cased. But once I decided I wanted a display and button, there was no reason for the smaller form factor. Also, having something a little bigger/heavier helps when you hang it off a IDC 40 cable.

1665422583793.png

I do agree we should try to stick to THT builds for hobbyists. While I find 0805 SMT easy to assemble, no real reason to go that route with current component availability (and pricing) for THT parts and it allows more people to "do it themselves" which I find to be the more satisfying part of this hobby. One of the reasons I also created this project for the Atari crew, https://github.com/djtersteegc/fujinet-devkit-shield
 
Bitly said:
I'm not a fan of surface mount connectors, in particular when they are subjected to mechanical stress (broken solder joints). The Arduino connectors would probably be okay, but the ribbon connectors could be an issue unless they were suitably strain relieved.

CW
Click to expand...
I haven't seen any 40p IDE connectors that are SMT and have attached wings,etc for additional mounting hardware attachment.
I was just thinking of a standard 40p IDE shrouded box header. Could go back to thru hole, but that would mean more hand soldering.
Once the switch is made back to a 40p thru hole, and with all the Arduino thru hole connectors, soldering in all the discrete parts as thru hole is not that big a deal...
 
Damn you AK6DN and your SMT musings! :) Spent a few minutes and did a rough fit test of the rest of the components on that Mega 2560 Pro Embed board design I shelved and it's just all so nice (assuming it can be routed on two layers). Only the (full size) SD card connector and larger caps on the other side. Just begging me to now route it and build it for no good reason.

1665441287348.png

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