Pro-2004: Found myself a rare gem!

[GadgetGeek]

I had a 2004 too that I bought new from Radio Shack. Wish I never got rid of it. I did a bunch of mods to it too. Lots of luck with it.

 

[videobruce]

I have had two of the 2004's without any problems. Other than one of them needed a replacement EL panel and had a dirty volume pot (nothing unusual). I'm wondering if it was a certain manufacturing period when the cold solder joints problem existed.

And I did numerous mods to both, one more so than the other including stacking a 2nd memory chip on top of the existing one, lifting the CE pin running wires to a toggle switch to activate one or the other doubling the channel storage from 400 to 800. That was a unpublished mod that Bill did thru numerous correspondence bewtween himself and me in the late eighties/early nineties. And still NO bad solder joints.

 

[Ubbe]

I don't know if it's in any of Bill's books, but a cool mod would be to use the switch voltage that goes between 0v and 8v in the PLL circuit that are used for the 1000-1300Mhz range, that probably no one uses, and have that trigger a flip-flop IC and its two outputs goes to those two piggybacked memory IC's chip enable. Then you program a 1300Mhz frequency to channel 400 in both banks and it will toggle between the two memory banks and make a 800ch scanner. Add a LED or two to the flip flop output to indicate which bank that are in use.

Instead of the flip flop you can use a decimal counter IC and control even more piggy backed memory IC's. Wire a switch to the inhibit pin of the flip flop or counter IC to stop the bank switching if only one bank are needed for the moment.

/Ubbe

 

[videobruce]

It's kinda hard to see since those wires are above the chips, but to the upper left of that system processor is the Toshiba memory chip(s) I was referring to.
That coaxial cable from that shielded enclosure is the 10MHz output mod. (The covers for those shielded boxes were removed for the pics.)