Deaf Atom?

discussion of games, software, hardware & emulators relating to the Acorn Atom and Acorn System machines.
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Lusciousthelock
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Deaf Atom?

Post by Lusciousthelock » Wed Sep 07, 2011 7:16 am

I've never been able to save and load software via cassette on my Atom, so sat down last week and tried to get to the bottom of the problem.

I have a nice old WH Smiths data recorder which has a tape monitor so I could check whats produced. Initially with the Maplins 5 pin din to 2 jack plugs cable, whilst saving the ouput was all crackly and the levels went up and down. I cleaned out the socket as best I could the set about deconstructing the cassette leads so their were only three pins and soldered the connections. I can now save, providing I remove the load lead from the recorder or that causes the sound level to drop?

My problem now is that I cant load :( How can I tell what sort of signal my Atom is recieving because nothing happens? I cant tell whether my saved signal is too high/low or what my Atom likes to read? Feels like my Atom is just being ignorant lol.

Are their and simple programs I could use to test the input from that socket? Also would it be worth me trying to replace the cassette socket itself, maybe corrosion has set in and is their a modern alternative?

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IanS
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Re: Deaf Atom?

Post by IanS » Wed Sep 07, 2011 7:33 pm

The simple steps described in section 1.10 of the manual are a good way of setting levels and seeing if your atom is saving and loading.

http://members.casema.nl/hhaydn/howel/A ... tap_01.htm

Lusciousthelock
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Re: Deaf Atom?

Post by Lusciousthelock » Wed Sep 07, 2011 7:39 pm

Is that in Atomic theory and practice? I dont remember seeing that thanks!

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oss003
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Re: Deaf Atom?

Post by oss003 » Wed Sep 14, 2011 1:26 pm

Hi there,

First you have to be sure that your cassette head is positioned ok. You can test this by playing an Atom cassette and listen to the output sound on a speaker. Then try to adjust the screw for positioning the head so that the sound is as clear as possible.

You can also improve the cassette ouput signal by using a filter, see attachment. I've build mine into the plug.

To test it you can use the program from Atomic Theory and Practice as mentioned before.

Greetings
KC
Attachments
Atom filter.PNG
Atom Cassette filter
Atom filter.PNG (13.09 KiB) Viewed 1150 times

Lusciousthelock
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Re: Deaf Atom?

Post by Lusciousthelock » Thu Sep 15, 2011 12:52 pm

The problem I have is that when the inputs are connected to a cassette recorder with a tape monitor function, the computer seems to generate a constant high pitched whine- lika data from saving and you can hear a faint chirp as keys are pressed. If I create a small program and save this then you can hear the program being saved inturrupting the whine and then the Atom is finally silent-ish as their is some slight crackling. Loading back into the Atom, it doesnt seem to hear any signal at all not even producing results given from the manual example above to produce x's. Completely deaf!!!

When I have time (please god, let me have some free-time soon) I'm going to get a mono jack plug and solder two pins onto each wire so I can test each pin individually.

Why would I get a constant whine- could the positives and negatives be the wrong way round ???

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danielj
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Re: Deaf Atom?

Post by danielj » Thu Sep 15, 2011 4:14 pm

Lusciousthelock wrote:The problem I have is that when the inputs are connected to a cassette recorder with a tape monitor function, the computer seems to generate a constant high pitched whine- lika data from saving and you can hear a faint chirp as keys are pressed. If I create a small program and save this then you can hear the program being saved inturrupting the whine and then the Atom is finally silent-ish as their is some slight crackling. Loading back into the Atom, it doesnt seem to hear any signal at all not even producing results given from the manual example above to produce x's. Completely deaf!!!

When I have time (please god, let me have some free-time soon) I'm going to get a mono jack plug and solder two pins onto each wire so I can test each pin individually.

Why would I get a constant whine- could the positives and negatives be the wrong way round ???
It does actually give a constant whine, so that's quite normal!

d.

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oss003
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Re: Deaf Atom?

Post by oss003 » Thu Sep 15, 2011 8:11 pm

If attached a WAV file, recorded from an original Atom so you can hear if your output differs from this one.
Typing should not interfer with the tape output. The only common thing between typing and cassette output is the 8255. It could be that your 8255 is defect.
It can also be that your cassette cable is not shielded (connected to pin2) properly.

Greetings
KC
Attachments
Hyperviper.rar
(2.46 MiB) Downloaded 77 times

Lusciousthelock
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Re: Deaf Atom?

Post by Lusciousthelock » Sat Sep 17, 2011 11:12 am

Thought I would play with the Atom using my PC as a cassette recorder and it hasnt gone very well :(

Okay attached is a recording made from my Atoms cassette port connected to my pc's mic socket. It makes that whine continuously, and I then type in the example from the manual to produce x's

do bput a,88; wait; wait; wait; wait; until 0

Which is the bleeping you here after 20ish seconds

I then tried getting my Atom to listen with-

do print $bget a; until 0

Only that didnt work on my Atom... And now doesnt on my PC somehow the Atom has blown my soundcard as the sound ouput is all crackly :( Bugger.
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test.rar
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danielj
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Re: Deaf Atom?

Post by danielj » Sat Sep 17, 2011 11:56 am

Lusciousthelock wrote:Okay, thought I would play with the Atom using my PC as a cassette recorder and it hasnt gone very well :(

Okay attached is a recording made from my Atoms cassette port connected to my pc's mic socket. It makes that whine continuously, and I then type in the example from the manual to produce x's

do bput a,88; wait; wait; wait; wait; until 0

Which is the bleeping you here after 20ish seconds

I then tried getting my Atom to listen with-

do print $bget a; until 0

Only that didnt work on my Atom... And now doesnt on my PC somehow the Atom has blown my soundcard as the sound ouput is all crackly :( Bugger.
Hmm... Okay, not sure about what it did to your PC sound card, but if it's not listening it could be a shot, or loose, op-amp (the LM358 in IC46). I'd first try removing it, gently cleaning up the pins with some very fine wet and dry, making sure all's nice and clean, then reseating it. You can do the same with the 8255 (IC25), but be careful and gentle as it's quite easy to bend the pins on the 40 pin ICs. If that doesn't help, I'd probably try swapping IC46 out for a brand new one:
http://www.ebay.co.uk/itm/6-x-LM358N-Op ... 1074wt_922

Are you absolutely sure all the pin connections are right for the lead too? Seems output's right, but just double check that it's wired properly for the cassette in.

One of the beautiful things about the atom is its simplicity. Armed with the circuit diagram and a bunch of spare ICs you can probably trouble shoot and fix most things. First thing to try (as I was advised though) is making sure the ICs are properly seated and the pins are all sparkly and clean.

Hope this helps,

d.

circuit diagram here:http://www.bbcdocs.com/filebase/hardwar ... iagram.png

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oss003
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Re: Deaf Atom?

Post by oss003 » Sat Sep 17, 2011 1:14 pm

I converted your WMA file to a WAV file and tried:

Code: Select all

do print $bget a; until 0
in Mess. This works so your output is ok.
What you can do to test is looking directly at the 8255-port:

Code: Select all

DO P.&?#B002U.0
Then play the soundfile at the Atom input and you should see a lot of 20's printed on the screen, after a while there must be some 0's printed.

Wait a minute..... Is your AtoMMC interface active at BREAK?
I'm not sure if this interferes with the cassette system but I'll ask Charlie.
To be sure, test it without the AtoMMC interface.

Greetings
KC

Lusciousthelock
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Re: Deaf Atom?

Post by Lusciousthelock » Sat Sep 17, 2011 4:09 pm

Thanks for the advice so far, I'm going to try and de-solder a few things to make sure everything is clean etc. When I purchased my Atom I know a few chips had dropped out and it was easy to place them all back together but maybe something has caused a dodgy connection along the way so i'll pull ic25 and ic46 for a looksee, maybe order spares- nice that they're still available :)

Sadly I had the loading problems before I got the AtoMMC, and it never bothered me before but its only recently I've wanted to save and load stuff I'm working. This Atom has always been a bit flakey lol

My tape leads were standard 5 pin din to 2 3.5mm jack plugs from maplins. The leads I tested with today were ones I made using a mono jack plug with some speaker wire soldered to two pins to fit the socket so I could connect to the correct holes (thought maybe maplins had supplied me with bent pins or something). Sadly both leads provided the same results. Just a quck question though, on a 3.5mm jack plug is positive forward middle or side? just incase thats whats blown my soundcard- seems worse now d'oh!

more experimentation

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oss003
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Re: Deaf Atom?

Post by oss003 » Sat Sep 17, 2011 5:39 pm

You can find the connections at:

http://en.wikipedia.org/wiki/TRS_connector

at: Tip/ring/sleeve terminology

Greetings
KC

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1024MAK
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Re: Deaf Atom?

Post by 1024MAK » Sat Sep 17, 2011 7:54 pm

Lusciousthelock wrote:Thanks for the advice so far, I'm going to try and de-solder a few things to make sure everything is clean etc. When I purchased my Atom I know a few chips had dropped out and it was easy to place them all back together but maybe something has caused a dodgy connection along the way so i'll pull ic25 and ic46 for a looksee, maybe order spares- nice that they're still available :)
Some are so widely used, that it takes a long time for them to fall out of use.
Lusciousthelock wrote:Just a quick question though, on a 3.5mm jack plug is positive forward middle or side?
Err, there is no positive or negative as such as these are low voltage ac signals (see http://en.wikipedia.org/wiki/Alternating_current). On the plug part, the end (known as the tip) is the "signal" "line". The longer section that then turns into a metal threaded section where the cover screws onto is the "earth", "common" or "0V" (as in zero voltage) for the return current. See picture (yes this is for a stereo plug, but you should get the idea :mrgreen: ).
3,5mm jack.gif
3,5mm jack.gif (72.54 KiB) Viewed 1007 times
Lusciousthelock wrote:just incase thats whats blown my soundcard- seems worse now d'oh!
Sound cards are mostly designed to take low level signals from either line output channels, or microphones. The outputs from mono cassette tape recorders and from the computers that use cassette tape recorders may produce too strong a signal (too loud :shock: ). Always start with the volume control set low when using a mono cassette tape recorder. When using the output from a 8 bit computer, you should really use a resistor or a variable resistor (also known as a potentiometer - see http://en.wikipedia.org/wiki/Potentiometer) to adjust the level (I can do a diagram if you want).
Having said that, some sound cards can handle such signals. If yours still works, but the sound is no longer "clear" or there is noise or distortion, then you have damaged some of the components on it. It may be repairable, but if it was a cheap one it is easier to just buy a new one.
Mark K.

Lusciousthelock
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Re: Deaf Atom?

Post by Lusciousthelock » Sun Sep 18, 2011 3:22 pm

Oooo! That describes my souncard all scratchy- like a blown speaker. Nasty onboard thing anyway, went out and bought a nice new one this morning. Think I'll stick to running the Atom on a cassette recorder lol. Anyone recomend a digital recorder of some sort?

I've cleaned the chips and reseated and checked solder joins but couldnt see anything obvious- have not had chance to plug back in yet to test but will try running some of those examples again this evening. If no luck their then I'll order some chips.

The only reason I asked about the 3.5mm jack plug was to be sure I wired the common and live the right way round incase that was the issue. I actally found the history of the humble jackplug quite interesting. I never realised that the jack connection was so old :) http://en.wikipedia.org/wiki/TRS_connector thanks KC.

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