14 replies to this topic

[yell0w_lantern]

I mentioned in a nother thread that my 2600 junior died.

I can't bear the thought of throwing it away so I am considering replacing the chips in it.

Does anyuone know where I can source a 6507, 6532 and a TIA chip?

Are there modern equivalents of the 6532 and 6507 that I can use?

[GroovyBee]

The cheapest (probably) and easiest route would be to get a working junior from ebay and swap motherboards, You could also buy another defective console in the hope that it has different faults to your own and then Frankenstein them together.

[bust3dstr8]

Before you start changing chips blind you should put a probe on them to see if they are actually faulty.

[yell0w_lantern]

No probe and I don't know how to run one anyway.

Essentially, it is an AV modded Jr that worked last year but doesn't work now. All the solder connections are solid. I redid the ground for Out. There are no obvious broken traces or other damage to the board. I cleaned all the contacts but all I get is a black screen without sound. My conclusion is that a chip went bad.

Edited by yell0w_lantern, Wed Dec 21, 2011 3:35 PM.

[bust3dstr8]

Do you have a multimeter you can use?

Edited by bust3dstr8, Wed Dec 21, 2011 3:53 PM.

[yell0w_lantern]

My brother-in-law has one. I doubt he remembers how to use it.

[GroovyBee]

Who fitted the AV mod?

[yell0w_lantern]

I did it using the Longhorn Engineer guide and board.

[GroovyBee]

Can't you remove the mod and fit it to another Jr?

[bust3dstr8]

yell0w_lantern, on Sun Nov 6, 2011 12:37 PM, said:

Over a year ago I installed a Longhorn AV mod on my Atari Jr. It worked fine for a while (several months?) but then I had to start tapping it when I started it up so that I would get picture.  I hooked it up after several more months and now I get absolutely nothing. The screen stays black when I turn it on although the power LED turns on; no sound. I get the same black screen with or without a cartridge. I even tried cleaning a couple of carts. I tried the Harmony cart too.  I even considered it might just be a video problem so I pressed reset half expecting to hear a game start but no such luck.

I opened up the console and checked the ground which turned out to be a little loose so I resoldered it but that did nothing. I tug tested the wires and examined the traces on LE's board but everything looked okay. No loose components either.

I'm wondering if a chip died or something. Anyone seen this before?

From the sound of things with the console needing to be smacked around there is a loose connection
somewhere. You said the display was black. Does the screen flicker as you power up the unit?
If no I would check continuity from the display chip to the cables.

If yes I would check continuity of the cart slot pins, since the console is not detecting the cartridge.
http://gamesx.com/wi...matics:2600cart

Check the traces from the addresses and data lines back to the chips and check the ground/OE lines.  Good traces will read near zero ohms.(some meters will have a beep function also)

With the console on and a cart in find test points for pin6 and pin11. Set the meter to DCvolts.
Pin 11 should read close to +5V and pin6 shoud read +2.2V to +5V.


If you want to test the indivudual chips you will need a logic probe. They are fairly cheap ($20) and
come in handy for us classics collectors.

GL

[Trinity]

Best Electronics sells the chips.

  If you can figure out their website.......

http://www.best-electronics-ca.com/

[Keatah]

Could also be latent static damage. Can take months for it to show up, as the metal pathways "corrode" when electrons flow through them.

[yell0w_lantern]

GroovyBee, on Thu Dec 22, 2011 7:53 AM, said:

Can't you remove the mod and fit it to another Jr?

The point is I hate to just junk it.

[jdrose]

This is a difficult store to navigate but I did find a TIA listed. Might give them a call.

(CO104444D - UM6525N ("TIA" 2600))
http://www.best-elec...om/custom-i.htm

You may want to invest in a digital probe. Affordable, handy and easy to use. You are basically looking at on and off states of pins. Ones and zeros.

[daberbaber]

I have 6532s but as stated before, you need to see if the console is actually clocking the CPU...on other 65XX systems, you can tell by stripping them down to the bare minimum and observing the minimual signals/outputs.  If you don't want to junk it, then sell it for parts on ebay and hope someone sees the value.  Modding a system always makes it harder for that to happen.  I'm wondering if there would be a use for a card inserted into the cart slot to tell if the MoBo is actually looking for stuff and therefore working?  I have some experience in this but not on this particular machine.  An oscilloscope is actually a great tool if you can get one or use one as you can look at the signals in real time and see what they are doing.  In this case, you could tell if the oscillator is actually oscillating and that would be a cause of no output/no anything.  I just located my MagiCard from 1981 and am looking to see if a clone of this would be useful as a diagnostic tool modified somewhat like the PetVet is for the Commodore Pet.  If there is any interest I will look more into making them available.