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Micro Color Computer Dead (?)

R

raoulduke

Experienced Member
Joined
Jan 14, 2015
Messages
356
Location
New Jersey
I bought my MC-10 boxed at a yard sale for $5 15 or 20 years ago. It had an RF adapter but no AC Adapter. So I never actually got to turn it on, and then forgot about it for decades. I started to look for an AC adapter a few months ago. It's an odd one: 8V 1.5A. Finally I found a cheapish 8V 2A AC Adapter and got it. When I fired it up today connected to my Apple RGB Monitor, nothing. Then I got an RF modulator and noticed minor interference on the TV (when I flipped the switch), but no obvious response from either the computer (I don't know if it's supposed to do anything) and no actual picture on the TV.

I unscrewed it and looked inside but I don't know what I thought that was going to accomplish. Any ideas? Sorry I have to plead total ignorance. I've taken the cases off of my Models III and 4 just for checkups but no real maintenance, but I really have no experience with TRS-80 hardware let alone the Micro Color Computer.
 
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Someone at least tell me it is in fact 1.5A min and not max... because the inverse would probably net a convenient explanation.
 
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Does the micro colour computer want 8V DC @ 1.5A or 8V AC @ 1.5A?

If you bought an 8V AC adaptor and it wants DC then there is your problem. An owner of a micro colour computer can check this out for you (I don't have one).
 
raoulduke said:
When I fired it up today connected to my Apple RGB Monitor, nothing. Then I got an RF modulator and noticed minor interference on the TV (when I flipped the switch), but no obvious response from either the computer (I don't know if it's supposed to do anything) and no actual picture on the TV.
Click to expand...

The MC-10 most likely is working, the AC adapter you got is the correct one.

The problem - following your what you wrote - is that the computer puts out a TV standard NTSC signal, channel 3 or 4, your Apple RGB monitor won't know what to do with such a signal - a standard analog TV is all you need.

-- RP
 
So maybe there's a mismatch between the RF modulator and the MC-10, which also has a channel switch - because I tried it on two TVs after the monitor.

That's not it.
 
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raoulduke said:
So maybe there's a mismatch between the RF modulator and the MC-10, which also has a channel switch - because I tried it on two TVs after the monitor
Click to expand...

What RF modulator are you talking about? are you setting some device in between the MC-10's output RCA jack and the TV set?

-- RP
 
Get an RCA to F-connector adapter, like this...

rca_coax_adapter.jpg


...and connect the MC-10's RF output directly to the antenna jack of a TV tuned to channel 3 or 4.

If there are any left in your area, Radio Shack sells that adapter, as part number 278-276.
 
The RF mod I found is a GE one with its own AC adapter and a channel selector. It has coax in and out to TV and an RCA video in (also audio).

I will get that direct adapter and retort back. Both Radio Shacks I knew about are gone.
 
If the GE one takes power, it's an RF modulator (composite video to RF), and you need a video game / antenna switchbox. It shouldn't require any power, and should be about 3/4 inch thick, by 2 by 3 inches. Or you can use a direct connect adapter, the MC-10 like many old video game systems puts out channel 3 or 4 RF at 75 ohms on an RCA connector.

The RCA to F adapter you need is available for $5 from Amazon: http://www.amazon.com/C2G-Cables-27312-Female-Adapter/dp/B0002J25OI
 
It seems Radio Shack has totally disappeared from NJ. Just ordered an RCA to F adapter. Thanks. (The machine may still be dead, though.)
 
raoulduke said:
Someone at least tell me it is in fact 1.5A min and not max... because the inverse would probably net a convenient explanation.
Click to expand...

Also, take a look at the polarity (if its DC voltage out) of the tip that plugs into the MC-10. Make sure that the tip matches what the input wants

(+/-) on the inner tip and the barrel...
gwk
 
How many are in business... because 3 of the 4 I checked still say or imply they're open on google maps: https://www.google.com/maps/place/RadioShack/@40.653296,-74.346075,13z/data=!4m5!1m2!2m1!1sRadio+Shack+near+07090!3m1!1s0x89c3b18529476c23:0x45a3714fc7150e10
https://www.google.com/maps/place/RadioShack/@40.653296,-74.346075,13z/data=!4m5!1m2!2m1!1sRadio+Shack+near+07090!3m1!1s0x89c3b3a58c1b844f:0x22a837121271206a
https://www.google.com/maps/place/RadioShack/@40.653296,-74.346075,13z/data=!4m5!1m2!2m1!1sRadio+Shack+near+07090!3m1!1s0x89c3aff81d29e03d:0x88f8fe4a669f5064

[I'm afraid I don't really want to check another 219... lol]

Gwk: the adapter shows + on the inner tip and - on the barrel [thank you for that, by the way, I have never noticed that iconography before; obviously very useful]. However, the MC-10 doesn't have an equivalent label, so I don't know what it wants.

*Found this place: http://mc10archive.com/ and sent a request for info on the AC Adapter/machine's polarity.
 
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raoulduke said:
How many are in business... because 3 of the 4 I checked still say or imply they're open on google maps
Click to expand...

I got that screen capture directly from Radio Shack's web site, whose new tag line is "RadioShack is open and here to stay! Over 1,700 convenient locations near you."
 
raoulduke said:
Gwk: the adapter shows + on the inner tip and - on the barrel [thank you for that, by the way, I have never noticed that iconography before; obviously very useful]. However, the MC-10 doesn't have an equivalent label, so I don't know what it wants.
Click to expand...

Well, I found the WikiPedia for the MC10, and it clearly states:

*************Power 8V AC 1.5A**************

So I guess we know why this isn't working!!!

https://en.wikipedia.org/wiki/TRS-80_MC-10#Specifications

You'll have to ditch the DC PS, and find an AC one--at least you won't be tearing hair out, trying to figure what's wrong...

gwk
 
VWestlife: their website lists 5 within 10 miles; the first is one that is closed; three are Sprint stores; 1 I'll call tomorrow. [lol... not convenient at all; though I do kind of wish the first one still listed on their website was open]

Griffk: Ok. It took me a minute to follow you. I'm not really electrically knowledgeable.* So have I fried it anyway?

Any advice on where to get an AC plug (is that what what I'm looking for is called?)?

*Though honestly it just never dawned on me that AC adapter would thus be adapting from AC (to DC). So I don't really know what I'm looking for, then... I've never heard that called anything other than an 'adapter' even when outputting AC. Wiki said "AC plug" but that didn't do much for eBay.
 
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raoulduke said:
Griffk: Ok. It took me a minute to follow you. I'm not really electrically knowledgeable.* So have I fried it anyway?

Any advice on where to get an AC plug (is that what what I'm looking for is called?)?

*Though honestly it just never dawned on me that AC adapter would thus be adapting from AC (to DC). So I don't really know what I'm looking for, then... I've never heard that called anything other than an 'adapter' even when outputting AC. Wiki said "AC plug" but that didn't do much for eBay.
Click to expand...

Ok, sorry if I was not being clear.

Whenever we talk of "Adapters", we usually mean "adapting" 110VAC/220VAC -> *Something Else".

In this case you bought an AC Adapter that converted 110VAC to 8VDC.

What you REALLY need (since the specs show power input -- *at the side of the computer* as 8VAC @ 1.5amps), is an Adapter that is 110VAC->8VAC @ 1.5Amps(or more).

Since the input power should be 8VAC, I doubt you fried anything in the computer with a DC source (if it was the other way around you could have done damage), so I wouldn't overly worry--you might have fried the Adapter you have, but probably not the computer.

Do a search on: "adapter 110VAC 8VAC" and look through the results for an 8VAC/1.5Amp output or better-there will be no polarity(+/-)....

gwk
 
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Not sure the barrel connector on the end will fit your computer, but the spec is right.

120VAC in -> 8VAC out @ 16VA (Or ~2A)

Don't get too confused about the 16VA. Basically that is a power rating (apparent power) which has to do with power factor & a lot of other stuff that doesn't matter in your case. Since you have 8VAC out and power in this case is roughly equivalent to voltage times current -> 16VA/8VAC = 2A.

Also it's fairly doubtful you would have hurt the computer. Usually the transformer windings can take quite a punishment compared to the el-cheapo switchmode DC power supplies.
 
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