Understanding TurboPad components

OldRover · 02/12/2008, 12:21 PM

/turbopad.jpg

Okay, I know what most of this stuff is. But the component at R103 is unknown to me. I've seen these things before but never had any idea what they were. So...what the frig is this thing?

EDIT: And for the record...it's labeled "A 473G". Google has turned up little on this.

Game-Tech.US · 02/16/2008, 02:57 AM

My best guess is that its a resistor bank. Biggest clue is the label, R103, R being short for resistor. I took apart a tg16 and duo controller, but they aren't like the one you posted a pic of, what is it from?
aka

Turbo D · 02/16/2008, 03:03 AM

that and the resistors to the left of it are labeled R101 and R102

OldRover · 02/16/2008, 09:20 AM

Quote from: akaviolence on 02/16/2008, 02:57 AMwhat is it from?

It's a TurboPad, it's just an older one I think. Other pads I've seen use surface mount single resistors. Yes, it does appear to be a resistor network chip. Now to find someone who carries this one...or a suitable replacement.

guyjin · 02/16/2008, 03:08 PM

you can't replace it with a series of individual resistors, or is it more complicated than that?

OldRover · 02/16/2008, 09:07 PM

Quote from: guyjin on 02/16/2008, 03:08 PMyou can't replace it with a series of individual resistors, or is it more complicated than that?

Probably could, but I don't know exactly what type of resistor network this is. There are several different arrangements. But judging from the presence of a + pin, I'm going to guess that it's a common-in type. I would have to have a newer pad to see how the surface-mount resistors are wired, but I don't have one...

Game-Tech.US · 02/17/2008, 12:19 PM

OK, I took one of mine apart again to show pics and give a run down of components for ya...
I had to make the pics low res to post but can email higher res pics if you need em.
I also wont gurantee the accuracy of the results since all measurements were made while compents were all still connected to each other on the board...
R701 888
R702 885
R703 878
R704 47.6K
R705 47.1K
R706 47.4K
R707 47.3K
R708 47.1K
R709 47.1K
R710 47.2K
R711 685
R712 685
R713 606
R714 330
R715 329
R716 329
R717 328
C701 16v 10uF electrolytic
C702 ? 104Z
C703 ? 104Z
IC701 Toshiba 8845H 74HC157AP
IC702 Toshiba 8927H 74HC163AP
Cap on pins 2-3 of IC163 ? B821
J710 is odd - like 2 chokes in place of a jumper - 0 ohms

OldRover · 02/17/2008, 04:16 PM

Thanks for the info, akaviolence. The capacitors look to be the same on both boards, The 104Z capacitors at C702 and C703 are .1uF with +80%/-20% tolerance. Those should be easy to find. J710 is a really weird one...why put chokes there? I don't get it. That's not in the original design.

Game-Tech.US · 02/17/2008, 07:13 PM

To be clear, I dont know what they actually are, actually look more like 2 unmarked diodes but had 0 resistance with a dmm.