Bikerbob's H5 C1 build

[Bikerbob]

OK so otherwise.. run a longer wire to the pin on JP18.. with the * correct?

Yep. But IMO remove the wire from the drive and just jumper JP18, JP19 and get 720k working first.

OK.. good idea.. eliminate variables.

[Bikerbob]

ok, so I removed the wire, and jumpered p18. So I am set at 720k now.. it will copy.. that works.

Kobold 3.5 will error with 2 bombs if I try and format.. it was doing that before and is doing it now.

Can I confirm.. can anyone else format with Kobold on a Phoenix board?

James

[exxos]

What does fcopyiii say when formatting ? It will give an actual error normally.

Also just try formatting and pressing down on each chip one by one to see if you can narrow down anything which gets better or worse while trying to format.

Also check the R/W input to the DMA goes back to ( I assume, can't check on my old tablet the schematics ) RW on the CPU Also another RW from the DMA to 1772.

Crashing with 2 bombs is odd.. I never used kobold, fcopy is my tool of choice.

[Bikerbob]

Hello all,

I have my H5 C1 back on the bench after doing a bunch of other stuff.

I am not having the floppy issue, it seems I was using a PC ROUND cable that had wires twisted (that I could not see) and that the cable was a lot of my floppy issues.

BUT - back to the sound issue. I have now removed all addons I had in.

I have a basic H5c1 with Dual TOS rom and Exxos 206 decoder. That has reduced the sound coming from the machine.. I have tried 3 different PSU in the machine, none seem to affect the output. I have tried different speakers, no change. I was using STD 13 pin ST monitor output - now changed to VGA and separate audio jack - no difference.

The easiest way to show this is video with audio - YES the speakers are turned up to maximum to really hear the issues. BUT I have tried loading Dungeon master from 4 machines, all load, and all have almost NO sound what so ever coming from when there is supposed be no sound.
The H5c1 - you can hear everything through the speakers, all sound from the machine is amplified, almost like there was a little microphone on the board.. things that should not make a sound - like the heads of the floppy engaging.. you hear through the speaker, all the seeks, etc.. and there is an overall background NOISE to use the machine, that NO other machine I own produces.

Lets assume since again - no one seems to be having the issues I am that this is a build error on my part.. Where do I look to solve this? I have followed all advice up to this point and I still have this issue.

James

[Bikerbob]

So no one has any idea what could be the issue with this?

I am sorry but I don't know how to do circuit level diagnostics here. I can build.. I can follow a diagram or schematic, but I don't know the logic of how it works. What could be causing the amplification of these sounds is beyond my scope?

I am in Canada, otherwise I would suggest sending it to some of you who have built a bunch of these.. maybe there is something I can't see for looking at it. I could post details pics?? if there is anything anyone wants to see.. Video on my Google drive of the issue??

James

[exxos]

The only 2 audio mods I have come up with you have already done, I can't suggest anything else as its impossible to remotely diagnose such issues. I don't see how you could end up with massive noises. Do you get the same with a stfm or STE ? The H5 should have less noise than those.

Short of sending me your board, I don't think there's anything else to try. But as you know , shipping to UK back and forth isn't going to be cheap

[Steve]

You could be having some ground-noise issues. I know in the UK we have a GND but some countries don't. I used to get lots of GND noise issues when I lived in Australia because basically nothing was grounded and the noise just passed from device to device ... Could this be an issue in Canada I wonder.

[exxos]

@Steve does have a point. To rule out gnd issues, you need to only have power to the H5 and use the ST2VGA adapter with headphones with a volume control. Or active speakers which must be battery operated.

I would double check the soldering on that 100k resistor also. You could try 10k but don't think it will matter. The symptoms still suggest the fix isn't done , but it is, so doesn't make sense unless there is a bad solder on the audio circuit somewhere.

[Bikerbob]

@Steve does have a point. To rule out gnd issues, you need to only have power to the H5 and use the ST2VGA adapter with headphones with a volume control. Or active speakers which must be battery operated.

I would double check the soldering on that 100k resistor also. You could try 10k but don't think it will matter. The symptoms still suggest the fix isn't done , but it is, so doesn't make sense unless there is a bad solder on the audio circuit somewhere.

So remember that I had audio issues in the first place right? the sound that would just disappear, so we added the inital resistor and now I have sound that is over amplified. Is there something to that?

James

[exxos]

So remember that I had audio issues in the first place right? the sound that would just disappear, so we added the inital resistor and now I have sound that is over amplified. Is there something to that?

Afraid I don't remember all the countless problems in all the countless threads

If you went from sound not working at all to it being over amplified then something seems problematic in the audio circuit. It is a separate problem to what the fixes solved.

I would suggest you check all the solder joints around the audio circuit under a magnifier and indeed continuity check and measure all the values. Probably check the resistors which are connected to GND first.

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Flux up and reflow any joints which looks suspect.