Atari 7800 refurbish and mod: Part 2 – cartridge slot and power connector

Last time I talked about refurbishing the case on my Atari 7800.

https://fieldmousetech.wordpress.com/2017/05/12/atari-7800-referb-and-mod-pt-1-referb/

This time I will be going over modding the cartridge slot (and why) and changing the power connector and power supply.

First little history on the Atari 7800 and how it pertains to my 7800.

The 7800 had two release dates: May of 1984 and then in 1986. In May of ’84 the system had a limited release in California. Around about that time Atari was sold to Jack Tramel. Tramel halted the general release so that he could focus on Atari’s computer line then later released the console in 1986.

Now why this is of interest to my console. When I got my 7800 I noticed that the label for the serial number overlapped a earlier sticker with an earlier serial number. My guess is that this console was one slated for sale in California then shelved or one that was returned from the California lot then resold as refurbished. Either way, I got a rather early machine.

Which means I got one of the machines that the cartridge slot was not big enough for some 2600 3rd party cartridges.

When Atari initially released the 7800 the  cartridge slot narrowed at the bottom slightly. Atari, and most other 2600 cartridges fit, but cartridges from Activision, Mattel and Imagic wouldn’t fit. Later models of the 7800 corrected this problem by not narrowing the slot at the bottom.

Since I have an early model, I have that problem. The way many people dealt with the issue was to shove the cartridge in as hard as they could. This, usually, resulted in cracking the cartridge slot, which is what happened to mine. See my previous 7800 post on how I fixed the crack.

The proper way of fixing the problem is to carve out grooves in the corners so that the wider cartridges would fit.

groves cart slot

In the -not too sharp- picture you can see where I trimmed out the edges. I used my Dremel tool to ground down the edges with a tube sanding attachment. Be careful to not grind out the top lip. The lip keeps the edges from cracking more.  I put the slot in a vise and put shims in the spaces between the outer and inner walls of the slot to keep it from cracking under the force of the vise. See my previous 7800 post for how I set up the vise and the shims.

If you don’t have a Dremel a heavy metal fill could do the same trick. I wouldn’t attempt cutting it with a knife as the plastic is to tough and brittle.

Now the power connector.

The 7800 uses a proprietary two pin connector for the power. It also uses a 9 volt, 1 amp, DC power supply. When I got the 7800 it did not have a power supply. One off eBay was from $15 to $40. I really didn’t want to spend that much money on something that, potentially, wasn’t working. Now I knew that a local Goodwill had a box of various power supplies, for $2.00 each, and I also knew that the 7800 was 9 volt, 1 amp. So I went to the Goodwill and sat on the floor and went through all of their power supplies looking for a 9v 1a. I got some funny looks. But, I did find a 9 volt 800 ma power supply, which I was determined was close enough. In testing, with no load, the power supply turned out to produce over 1 amp anyway.

That solved my power supply problem but did nothing for my connector problem. The connector wasn’t just incompatible with the bayonet connector on the power supply I just bought, It was also bent up and slightly broken off. To connector was also soldered to the motherboard which made fixing it more difficult.

So instead of changing the bayonet connector on the power supply I just de-soldered the two prong connector off the motherboard. Be careful to not try and force the 2 prong connector off the motherboard. You could damage the motherboard. Use your de-soldering technique and let the connector ease on out.

 

The 2 prong power supply connector was only attached to the motherboard at two spots so removing it was not to difficult. I soldered two wires in the place of the connector.

power finsig

I soldered the female bayonet connector, that matched the connector on the power supply, to the wires to the power supply.

pwr plug

Here is where I elected to place the new power connector; the bottom on the lip. You could place it where ever you wanted.

To show how brittle the plastic on the 7800 is, I drilled two stages of pilot holes for the connector plug with a slow drill press and STILL manged to crack the case.

Again the finished product.

all closed up

Next time I will go over the composite mod. The article will be rather long so be sure to settle in.

As always, use all safety precautions and these mods are AT YOUR OWN RISK. I do everything I can to make this blog accurate but use your common sense.

That’s it for now, ta.

Field Mouse

 

 

 

 

 

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