exxos's Atari, Amiga & retro forum

There's a hint in the name of PVC (poly-vinyl chloride) as to why when it breaks down it releases HCl... :-)

Whether it breaks down very much depends upon the precise chemistry used to make it, such as the polymeriser (the chemical compound used to cross link the vinyl chloride chains).

stephen_usher wrote: 19 Apr 2021 09:43 There's a hint in the name of PVC (poly-vinyl chloride) as to why when it breaks down it releases HCl... :-)

Ah! Yes of course! :lol:

Whether it breaks down very much depends upon the precise chemistry used to make it, such as the polymeriser (the chemical compound used to cross link the vinyl chloride chains).

Atari must have had a bad day when they ordered those if they affect all MSTE machines' hard drive mounting plate.
Probably the cheapest ones available.

If your Mega STe's hard drive LED bracket is rotted away, you might want to check
out this thread (long but covers replacing the power LED and the HD LED).

I did both and am very happy with the results. :)

https://atariage.com/forums/topic/30093 ... lacements/

To keep it really simple with the leds I would probably wire them both up as usual(4 wires) and use small flat square leds.
https://dutch.alibaba.com/product-detai ... 7127OTnF79
If you mod the new grommet a little bit you could add both leds without having the wires to close toghether as a short would not be nice.

If you would like a nicer sollution a single IC like a dual 2input NOR gate could work (you also need a resistor, a small cap and a piece of protoboard.
(correct me if i'm wrong or there is a better option)

Yes, I love simple solutions and appreciate your suggestion!
If the lighting is sufficient that way I'm all for it as electrically that would be the least time consuming. And a lot can be done with heat shrinking tubes, a rubber grommet and possibly some hot glue as well.

After some rust-removal it looks a whole lot better now:


Unfortunately there's not enough room between the metal frame and the LED-diffuser to fit two LEDs side by side. It seems I either have to mount a couple of LEDs sideways (not ideal to the lighting angle) or insert a PVC grommet/3mm LED as originally intended, but with a dual coloured type.
Finding a dual (or RGB) coloured 3mm LED with separate pins is a challenge....

I've ended up with a simple low tech "just get it done NOW" solution where I placed the two separate 3mm LEDs next to each other. The orange LED (SCSI HDD) is fine, but the green MonSTer CF-card LED is a little faint. No doubt a more modern, higher intensity LED would make up for the less than ideal placement angle.
The HDD LED is connected directly and permanently to the HDD while a home-made connector which takes care of the practical bit of being able to disconnect the MonSTer attached CF-drive LED whenever the MSTE needs to be opened up, allowing the LED to be disconnected before disassembling the MSTE top cover. I used hot glue to fasten the LED wiring to the HDD drive bay.
Not the most elegant solution, but it works (at least until I find a more sophisticated solution if I decide to go that way).

Regarding the PVC grommet: I measured a 3mm opening for the LED (actually the original LED was more like 2.5mm all the way while the 3mm LEDs in my parts box are a little wider at the bottom, but it shouldn't make much of a difference). Around 4mm diameter outside of the mounting hole and around 8.5mm wide at the widest. The metal lug opening's diameter is 4mm.


Here's the DIY cable I made for the LED which goes to the MonSTer board indicating drive activity from the Compact Flash memory card drive. I used two pairs of SIP sockets for this and heat-shrink tubing.


Here are the two LEDs placed next to each other underneath the metal lug. Note that I haven't used any hot glue on the LED diffuser plastic so I don't mess it up in case I want to revert my LED modification. Hot glue is used to fasten the wires.


Finally, here's what it looks like when the internal SCSI HDD is accessed:


And here's the green LED which indicated CF-card activity from the MonSTer board:

Works like a charm!
:dualthumbup:

Thanks.
Sometimes it's better to just get things done ;)

stephen_usher wrote: 18 Apr 2021 17:35 Remove the remains of that original PVC gromet, clean the steel up, paint the area so it doesn't rush any further and fit a 3mm PVC gromet (6mm external) into which you can press the LED.

Finding the right one apparently isn't as easy as I thought.
The one by RS components (which I posted about earlier) doesn't seem to be right after all. I'm trying to find them on eBay (preferrably in Europe as shipping from China takes forever -which is what you get for "free shipping"). You really need to order quite a bit from RS and similar places to justify the total costs.
The original grommet fits a 4mm hole while all the ones I've found on eBay so far need a 5.5mm hole.
Here's the original one for my MSTE HDD drive bay.