[Coco] Coco 3 with problems, can anyone help me troubleshoot?

Mike Rowen mike at bcmr3.net
Sat Feb 11 22:04:37 EST 2012


Looks like you already used audio on to test the cable. I had missed that in earlier post. Double speed issue sounds like a good one to check out.

On Feb 11, 2012, at 9:58 PM, gene heskett <gheskett at wdtv.com> wrote:

> On Saturday, February 11, 2012 08:58:10 PM Mike Rowen did opine:
> 
>> Have you checked your cassette cable?
>> 
> That is another possibility Mike, but if he can hear the tape in the 
> speakers hooked _to_ the coco, then I'd like to think the cable is good.  
> So the next question I'd have is, was the coco3 slowed to coco2 speed when 
> that tape was written, and its also slowed to coco2 speed before the tape 
> read is attempted?
> 
> Frankly, the noise performances of the CCR-81 and look-a-likes have always 
> disappointed me, a lot.  The DC magnet erase and bias setups on those put 
> so much noise and distortion on the tape that I have applied the same 
> theory to those that we used back in Model T Ford days, which was said to 
> have Christian Science oiling because you had to be a CS to believe the 
> cylinder walls got enough oil.  They never did.
> 
> So while my metal tape capable Sony dual deck machine didn't have an 
> interface that allowed its motors to be controlled by the coco, it was no 
> problem to start the deck in record mode, then hit the return key to start 
> the coco's output, stopping the deck when the prompt came back.  I have yet 
> to fail to read back such a tape even though it was only on one track of a 
> stereo deck, even when that tape was played back in a GE copy of that 
> CCR-81.  I even mailed out a few copies of some stuff to others who 
> reported they were flawless.
> 
> So, that brings us back to his problem.
> 
> Please give us a little better description of what that buzzing really 
> sounds like.  They should be rather raspy, with noticeable output from the 
> tweeters if you have that fancy a speaker set.  If it sounds like it has 
> been through a low pass filter, with no more highs to drive the tweeters 
> than you would get thru a phone circuit, I'd have to guess that one, either 
> the head was dirty and the tape is not making good contact, or two the head 
> is worn out, or the felt pressure pads in the cassette are missing. 
> Obviously a fresh cassette and a fresh recording would tell that tale.
> 
> The head being worn needs a quite strong magnifying glass to see if you can 
> actually see the pole piece gaps where they come together, usually much 
> much less than 0.001" and invisible even to a 100 power glass/microscope, 
> so basically if you can see the gap, running vertically on the face of the 
> head, its gone.  This will also be visible it the supposedly cylindrical, 
> well polished profile of a good head.  If it looks like its worn unevenly, 
> its safe to bet its worn out.  Even good heads are like diamond phono 
> needles, and gone in 500 to 1000 hours of use, unless it says Ampex 600 on 
> the deck, they were much thicker and could hold specs for 30k hours.
> 
> This is not to belittle Mark in any way.  Its even possible that a coat of 
> something atmospheric born is on the head after all these years, no fault 
> of Mark's at all, and that a decent cleaning and letting a fresh cassette 
> play through it full length to restore the polish might be in order.  Since 
> they are made of an alloy called mu-metal, its conceivable that they could 
> also "rust" like iron would but I've no clue what color it might be if that 
> is the case.
> 
> Wikipedia says this about the alloy:
> Mu-metal is a nickel-iron alloy (approximately 77% nickel, 16% iron, 5% 
> copper and 2% chromium or molybdenum)[1]
> 
> That 16% iron could be an oxidation problem over the 20+ years since these 
> CCR decks were made.  On iron, we call that oxidation rust but I'd have to 
> think its not anything but surface and an in-determinant color what with 
> all the other stuff, like copper which also oxidizes over time.  So will 
> the chromium which is why your cars bumpers have a coat of nickle over the 
> chrome to keep it nice & bright for a while.
> 
> The wiki article does not discuss its oxidation modes or properties.
> Another site does allude to it with this statement:
> 
> Mumetal is only moderately resistant to moisture and atmospheric corrosion,
> 
> And that seems to about the extent of available data since the rest of 
> those sites are interested in selling you some of it. ;-)
> 
> However, beware of 'cleaning tapes' those things are like 320 grit 
> sandpaper, every 10 seconds can take 50 hours off a heads life.
> 
> If the full length pass of a new 2 hour tape fixes it, toss that tape, its 
> now contaminated and having done its job, needs to hit the trash can.
> 
> Hopefully I've hit the rest of the bases here.
> 
>> On Feb 11, 2012, at 8:45 PM, haywire666 at aol.com wrote:
>>> I removed and thoroughly cleaned the gime chip and socket. no gook or
>>> noticable grime to speak of though when I started....
>>> 
>>> 
>>> Interestingly no more garbage screen bootups so cleaning the gime chip
>>> and contacts did something, but when I try to CLOAD the same problem
>>> happens (S character in upper left hand corner of screen) tape plays
>>> and machine locks in that state...
>>> 
>>> 
>>> Motor on/motor off commands work.
>>> 
>>> 
>>> audio on and audio off commands work.
>>> 
>>> CSAVING appears to work. At least I think so... With audio on, I hear
>>> a bunch of buzzing when what I saved is played back...
>>> 
>>> 
>>> Steven
>>> 
>>> 
>>> 
>>> -----Original Message-----
>>> From: haywire666 <haywire666 at aol.com>
>>> To: coco <coco at maltedmedia.com>
>>> Sent: Sat, Feb 11, 2012 8:20 pm
>>> Subject: Re: [Coco] Coco 3 with problems, can anyone help me
>>> troubleshoot?
>>> 
>>> 
>>> 1) I have a ccr radio shack cassette I just got from cloud9.
>>> 
>>> 
>>> 2) When I use audio on commands I can hear stuff from the tape, but
>>> its been years since I heard a data tape. Sounds right from what I
>>> recall.
>>> 
>>> 
>>> 3) When I cload, the tape indeed starts, I get an S in the upper left
>>> corner of the screen. The tape stays on forever. The machine's state
>>> never changes, even when I left it for an hour.
>>> 
>>> 
>>> 4) I don't have a prerecorded tape to check. I am just now getting
>>> back to cocos (My first computer love) after many years off...
>>> 
>>> 
>>> 5) I don't think its high speed poked, I boot the computer the cursor
>>> looks regular speed, when I try it from clean cold boot this happens.
>>> 
>>> 
>>> 6) Someone else suggested pulling and cleaning the contacts of the
>>> gime chip. Just got back from radio shack, got an extraction tool...
>>> so I'm trying that now.
>>> Pulled the chip, both the chip and the sockets contacts look really
>>> dingy and dirty... so I hope maybe thats it. I'm going to go work on
>>> this now will post results.
>>> 
>>> Thanks for everyone's help... Hopefully my poor coco3 will be feeling
>>> much healthier soon!
>>> 
>>> Steven
>>> 
>>> 
>>> 
>>> -----Original Message-----
>>> From: Arthur Flexser <flexser at fiu.edu>
>>> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
>>> Sent: Sat, Feb 11, 2012 6:54 am
>>> Subject: Re: [Coco] Coco 3 with problems, can anyone help me
>>> troubleshoot?
>>> 
>>> 
>>> You might narrow down things by using the AUDIO ON command to see if
>>> the tape sounds normal when it is saving and when you attempt to load
>>> a program.
>>> 
>>> Also, make sure you aren't in the double speed mode;  the cassette
>>> routines must be patched to work properly at that speed.
>>> 
>>> When you say it "just hangs", I assume you've verified that the tape
>>> is advancing properly?  Do the MOTOR ON and MOTOR off commands
>>> function?
>>> 
>>> Art
>>> 
>>> On Sat, Feb 11, 2012 at 5:12 AM,  <haywire666 at aol.com> wrote:
>>>> I have a color computer 3 with some problems. I thought it was a cold
>>>> solder
>>> 
>>> joint or something. Occasionally it would not boot right (I'd get a
>>> garbage screen) The real problem however is that once its working, I
>>> can save programs with csave to cassette, but when I try cload, I get
>>> an S on the upper left corner of the screen and then it just hangs.
>>> 
>>>> Has anyone seen this before? Can anyone give me some trouble shooting
>>>> tips?
>>> 
>>> Not being able to save programs (just bought a cassette for that
>>> purpose) is driving me kind of nuts.
>>> 
>>>> Steven
>>>> 
>>>> 
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>> 
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> 
> 
> Cheers, Gene
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
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