BeebSID

[Multiwizard]

It's.... Christmas and time for another disk mined from the HVSC vaults!

Feast your ears this December on the amazing hits of ABBA!

beebsid16.jpg

- PJ

Oh joy...

How do I execute a SSD file on a Beeb?...


Greetings, Wim...

[fordp]

I just select the Disc using *DIN xx press return. The type *SIDPLAY press return. Some discs have a different executable.

[Multiwizard]

I just select the Disc using *DIN xx press return. The type *SIDPLAY press return. Some discs have a different executable.

Thanks for the advice...

I have tried several XX options after *DIN , but I can't find the right one yet...


Greetings, Wim...

[oss003]

I think you first have to add the SSD image to the MMC file before you can select it with *DIN <nr>
You need a special program to do that.

Greetings
Kees

[Multiwizard]

I think you first have to add the SSD image to the MMC file before you can select it with *DIN <nr>
You need a special program to do that.

Greetings
Kees

So this won't do?..


Greetings, Wim...

[oss003]

No, you have to add the SID ssd to the BEEB.MMB file.

I think MMB imager can do this: http://www.msknight.com/bbc/mmc.html

Greetings
Kees

[oss003]

This program should work: http://www.g7jjf.com/public/MMBImager.zip

Greetings
Kees

[jgharston]

It's.... Christmas and time for another disk mined from the HVSC vaults!
Feast your ears this December on the amazing hits of ABBA!

Oh god! I was listening to Abba for hours while typesetting the HADFS manual back in 1994. Now I've got it playing while typing up my response to a candidate assessment review. (Which I should be doing instead of browsing here )

[mattyj]

Hello
Is the BeebSID kit / pcb / sid image etc still available to buy?
Thanks
Matt

[MartinB]

There's none of my original PCB batch left I'm afraid but Phill HS (prime on here) had a second batch made - maybe he has some of those left?

[JudgeBeeb]

Prime does indeed have some available. However, I understand he is rather busy at the moment; so you may need to be patient.

[danielj]

If you listen carefully, you can hear the screams of poor defenceless C64s fearing for their integrity every time beebsid gets mentioned.

d.

[MartinB]

C64 organ donation - it's what their owners would have wanted...

[1024MAK]

Shut you eyes, little Commodore's...

My BeebSID

Beeb SID (Phill's version)

And very good they are as well

Of course, this does mean I have to use an Atari STFM as a sentry in between my Beeb with the BeebSID and my C64 and C128 machines!

Mark

[JudgeBeeb]

My second SID chip arrived today (from a more reliable source) and this didn't work either. The same problem as before – the LM7805 got incredibly hot. I suspect it is more likely there is a fault with my board (rather than two different chips from different sources producing the same problem). I am going to have to see if I can trace the fault (when I have some time).

In the meantime, I have one question. I haven't included the pull-down resistor on pin 27 (audio out). I assumed it was unnecessary, as the datasheets seem to suggest that this is only necessary for the 6581 and I am using the 8580. Is this correct? In any event, I don't see how this could cause a problem of this kind.

[MartinB]

No, not necessary - I didn't even include that resistor on my original BeebSID schematic design.

I think you need to start with a very careful check of the integrity of your supply rails and the associated 0v returns.

[1024MAK]

It maybe helpful if you post some pictures (top side and underside) along with details of which power configuration you have opted for...

Mark

[JudgeBeeb]

I have had a very close look at the board under magnification and there do not appear to be any bridges, damaged tracks or poor solder joints. I am also not convinced that it is an inherent problem with the power rails. If that were the case, wouldn't one expect the problem to arise whenever I connected power? The voltage regulator seems fine when the power is applied without the 8580 in its socket. The LED lights up (and I assume the logic chips are drawing some very modest current). But when I power it up with the 8580 present, the heat from the voltage regulator escalates to un-touchable levels. The impression is that the 8580 is drawing a lot of power - but this seems unlikely for two chips from different sources.

I think I need to measure a few values around the circuit. Make sure that the voltages are correct and how much current is being drawn. I am also wondering whether it might be worth replacing the LM7805.

Trouble is, I need to first find some time to do this.

[hoglet]

What voltage are you feeding into to the board?

Is this regulated or unregulated?

I have a BeebSID 2.3 board from Phill fitted with a 8580 that works. I fitted a heat sink to the 7805, so it is expected to get hot.

It's just possible what you are seeing is normal.

This is probably stating the obvious, but:
- 6581 needs 5V on VCC (pin 25) and 12V on VDD (pin 28)
- 8580 needs 5V on VCC (pin 25) and 9V on VDD (pin 28)

GND is pin 14.

Have you confirmed these voltages are present (wrt pin 14), both without and with the SID Chip present.

Dave

[JudgeBeeb]

What voltage are you feeding into to the board?

Is this regulated or unregulated?

I have a BeebSID 2.3 board from Phill fitted with a 8580 that works. I fitted a heat sink to the 7805, so it is expected to get hot.

It's just possible what you are seeing is normal.

This is probably stating the obvious, but:
- 6581 needs 5V on VCC (pin 25) and 12V on VDD (pin 28)
- 8580 needs 5V on VCC (pin 25) and 9V on VDD (pin 28)

GND is pin 14.

Have you confirmed these voltages are present (wrt pin 14), both without and with the SID Chip present.

Dave

Thanks Dave. That is indeed the way I believe I have it configured. I do plan to check those and other things. The trouble is that I am getting home so late these days. Too much work and not enough fun.

[hoglet]

I just measured the VCC current draw of the 8580 on my BeebSID as 110mA .

If you are feeding the board with 12V, then the 7805 is going to be dissipating 770mW.

The ST L7805 I used has a thermal resistance of 50°C / Watt without a heatsink.

So at 21°C ambient the package would quickly reach temperatures of 21 + 50 * 0.770 = 59.5°C which is very toasty.

What type of 7805 do you have fitted?

Does it have a heatsink?

Dave

[JudgeBeeb]

I just measured the VCC current draw of the 8580 on my BeebSID as 110mA .

If you are feeding the board with 12V, then the 7805 is going to be dissipating 770mW.

The ST L7805 I used has a thermal resistance of 50°C / Watt without a heatsink.

So at 21°C ambient the package would quickly reach temperatures of 21 + 50 * 0.770 = 59.5°C which is very toasty.

What type of 7805 do you have fitted?

Does it have a heatsink?

Dave

I am using this. It has the standard small factory fitted heat tab; but nothing 'after-market'. I have not measured the temperature. But the first time I powered it up, it had been on for about two minutes before I momentarily touched it and recoiled. My finger was still sore for about an hour. I think that is more than 59.5°C. I would guess it was over 100°C.

[JudgeBeeb]

From the datasheet, I see its operating temperature is up to 125°C. I would guess it was either very near or possibly exceeding that.

(Measuring the actual temperature, is something I will do as well.)

[hoglet]

From the datasheet, I see its operating temperature is up to 125°C. I would guess it was either very near or possibly exceeding that.

You would surprised how hot just 60°C feels!

But you do have a heatsink fitted, so it shouldn't even be getting to 60°C.

Dave

[1024MAK]

You need to measure the input voltage, the output voltage (to see if the 7805 is in current limit or fold back mode) and the input current.

The power dissipation and therefore the heat generated by a series voltage regulator depends on the input current (determined mainly by the output/load current) and the input voltage. Typically, it's recommended to fit a heatsink to the metal tab of the regulator for currents of 100mA or more if the input voltage is above 8V.

The maximum temperature quoted in datasheets is normally the silicon chip temperature, not the case temperature.

Mark

[1024MAK]

This may be a suitable heatsink.

Mark

[JudgeBeeb]

OK. Although it was late, I couldn't resist giving things a try out. All the voltages checkout OK. It draws 20mA without the 8580 and 130mA with it in place. Temperature on the LM7809 was 28°C. The temperature on the LM7805 (after about 15 minutes) had reached 83°C. So not quite as bad as I thought. And...


...it works

Not entirely sure what was wrong. I think it may not like my DataCentre (*DTRAP seemed to solve the problem). But that isn't really the answer because it wasn't work on an entirely vanilla DFS machine either. So I will have to play around with that later. Also, I clearly need a heatsink

Thanks for all the help.

BTW, as a result of this palaver, I now have a spare working 8580. If anyone is interested...

[daveejhitchins]

pm sent . . .

Dave H

[1024MAK]

@lazarusr, good to hear that your BeebSID works

Now go and have some fun and stop toasting your fingers

Mark

[hoglet]

OK. Although it was late, I couldn't resist giving things a try out. All the voltages checkout OK. It draws 20mA without the 8580 and 130mA with it in place. Temperature on the LM7809 was 28°C. The temperature on the LM7805 (after about 15 minutes) had reached 83°C. So not quite as bad as I thought. And...

That current draw is very similar to what I was seeing (~140mA overall)

...it works

Excellent stuff, well done for persevering.

Definitely worth fitting a heatsink though, especially if this gets mounted inside a Beeb.

Dave