Cobra-matic : Retro Bakelite Phonograph

[Mach]

Berticus: I've got the drive torn down again and 486Hawk from austinmodders is guiding me. I got sidetracked on work stuff this week but will give the soldering a shot next week.

DaveW:, yes the ram is setup for dual channel but I set it up that way without really understanding what I was doing. I just followed the manual for installing the ram which said put them in the same colored slots

To enable Dual Channel mode with two or four memory modules (it is recommended to use memory modules of identical brand, size, chips, and speed), you must install them into DIMM sockets of the same color.

[Mach]

Too jet lagged to sleep last night so I had a go at the DVD Rom.

This has to be the toughest soldering that I've ever done. At 2.5x magnification, I could barely see the connections. How you guys do this I'll never know.

This is to move the dvd eject button to a limit switch on the lid. Those 2 black wires are 30 gauge.

For the tray sense switches, from this:

To this:

The switches are about the size of a pencil eraser.

If you ever have to de-solder something this small, Chip Quik works like magic.

Next up is the limit switch for the lid and computer code to sequence it all.

[Mach]

d_stilgar: Thanks for the rep!

And to the unnamed person who asked for a tutorial on the copper etching, will do. I've got another project waiting in the wings in which etching figures prominently.

I've spent the better part of a day getting the drive back in working order. I've been posting progress pics over at Austinmodders.com but haven't really given you guys a full breakdown. So here goes...

If you review the worklog, you can see that I cut a window in the top of a hub locking, tray loading slim line drive. This makes the DVD visible while its spinning (which is cool) and makes it look more like a record player (which fits the mod theme). The problem is in changing out DVD discs. Windows doesn't know a new disc is in the drive because the drive hasn't reset (a Windows (f5) reset doesn't work).

What make it reset? Pushing the button on the front and opening the tray which clues the DVD rom into the fact that a new DVD is coming. When the tray closes, it resets the drive. Its pretty simple actually. Making it reset without opening the tray is a little more difficult. Add to that the drive needs to stop before you can pull out the DVD makes it an interesting problem.

With the help of electronics kung-fu master, 486hawk, I've learned that you have to simulate the eject button press and simulate the open tray event. By soldering wires to pins 3 and 4 of the drive control header, and using a relay, then I can simulate the button press by shorting the two pins momentarily.

The header is found here:

A close up shot:

I used an ohm meter to test all 10 pins of the header with the button pressed and open to find that pins 3 and 4 were the correct ones. YMMV.

With that done, then I de-soldered the switches and soldered wires to the contacts. My drive had 2 switches but after testing, I only need to trigger one to reset the drive. The two images in the previous post describe what it looks like after soldering.

Lastly I had to remove the mechanisms that physically move when opening the tray. Wouldn't want it to pop open.

Before

After

Then I soldered on connectors for the switches and added a small limit switch to the lid to sense when its open.

I then sealed the entire underside with foil tape to keep out any dust.

It works as expected when connected the phidgets controller but I'll need to test further when connected to the motherboard to be sure it works properly.

Finally, here's the link to the austinmodders.com discussion.

http://www.austinmodders.com/modules...ewtopic&t=1467. Thanks again to 486hawk for all the help! To anyone who wants to try it, I hope the pics and description help. The only hairy part was soldering to the header. I was fortunate to have access to a decent soldering iron (Hakko 936) and a great deal of luck.

That gets me pretty much back on track which is seeing how badly I can plug up an airbrush with glow in the dark paint.

Till next time...

[DonT-FeaR]

nice work man... i would of put a break in the cd rom power lines and waited or it to stop the swapped discs and turned on again.... but ur way works to ???

[Mach]

Thanks for the comment. I tried cycling the power by disconnecting the drive. It still locked up Windows Explorer.

[blueonblack]

Wow. Just wow for the electronics work. I'd have been way too scared to try anything that small. Excellent work. +rep
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Mercedes-benz 260 d history

[Mach]

Thanks blueonblack! More luck than skill but I'll take it.

I've been modding, brain modding. Based on my last foray into circuit design, I've learned to ask first and cut second. It helps reduce the general TBCS confusion level.

So, here's my attempt at a circuit that gives a momentary pulse and then waits a period of time before opening the second relay. This is used to first simulate the eject button being pressed and the DVD rom tray opening. I'd appreciate comments on whether this is overkill or any changes that I should make.

I'm leaving this diagram in place for completeness. I was never able to get it working.

Note: R3 can be varied to increase the duration of the wait. The LEDS connected to the relays are there for testing purposes.

Also, I've got a normally open SPST switch on the lid of the CD. To make this circuit work, do I need to swap it for a normally closed SPST?

Oh yeah, I'm using Circuit Wizard to simulate the circuit. I picked mine up at Maplin's in the UK but it looks like its available in the US through Kelvin.com although more expensive than Maplins.

[Mach]

Thanks for the rep & comments d_stilgar & Xpirate

An update for your perusal.

Still waiting on a couple of parts for the DVD rom circuit so I took a look at another problem. When Cobra-matic up & running, the video card and HD were running on the high temperature side. (Both of which were passively cooled) I didn't like the looks of an add-on fan on the video card, so why not a new one, video card that is...

And one of these:

Only problem is the ram heatsinks and the fan leds are blue which don't fit the theme of the mod. The heatsinks were easy.

The leds took a little bit of effort, dremeling, and chipquick.

Silenx 60mm fan mounted on the HD:

Thanks for looking!

[DonT-FeaR]

great looks cool...

nice work with the leds man

[blueonblack]

Beautiful work, not sure why but lots of copper sure helps that retro look. Love that VGA cooler, I have those same heatsinks on my video card. I'm actually looking for a pretty copper cooler for it for transplant into Clockwork, the Accelero I have on it now is cool but not that pretty. What make/model is that?
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XJ