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Forums > C64 Coding > SID burn protection
2008-03-29 22:30
mogwai
Account closed

Registered: Mar 2005
Posts: 5
SID burn protection

I am planning to build a SID protection card in order to prevent more SIDs for travelling to silicon heaven.

goto80 and I was discussing the problem and he asked me to build something for him since he was burning so many SIDs during his performances.

Anyway, the reason for posting this topic in this forum is that I need as much information as possible regarding what is causing the problem. So I was wondering if you could give your stories about when you toasted your SIDs.

My guess is that it is caused by ESD. Since the C64 design is using a serial resistor connected to a transistor follower design on the audio output it is probably not caused by excessive current so my only theory right now is ESD when connecting the audio. However it is only a theory and I need as much input as possible.

If you have any nighttime horror stories about the time when your SID passed away, then please tell me. I need as much detailed info as possible regarding what you did, which cables were connected, to what, in what order or if you didn't do anything and it was just dead one morning etc.

Looking forward to your stories.

P.S. Sorry, accidentally placed the question on the coding forum. Don't know how to remove it. Reposting under general discussions.

 
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2008-04-28 01:29
Exin64
Account closed

Registered: Jan 2004
Posts: 24
Hmm, i wonder why this didnt came up yet.

I have read about a "sid protector" in a few magazines.

Mainly it disconnects the Input line and had some resistor all over the socket.

Also, if you connect something strange that gives some feedback signal to the SID output and input, that could fry the Filter. If the filter is fried, then you wont have much to hear.

Long long time ago, when i had my first C64, i think it already had some filter methods only partially responding. I wonder how that happened. But here are the details:

In Matehmatica, it plays only half of the channels at all, sometimes the only left channel produced garbage.

In most older games the sound was okay nsomewhat.

In the mood preview crack screen by Dytec or Acraise (The one with the light grey background and colorful oldskool logo above), only the melody was there. Without filters. Bass drum and other stuff was missing.

And so on.

Its the only sid that ever was totally broken at all.

Exin
2008-07-10 07:52
ready.

Registered: Feb 2003
Posts: 441
Dear all,
maybe I have come up with something interesting. Lately I had some discussions with different audio and electronic technicians. Combining feedbacks from car audio and radio amateur applications, I think a solution could be a ground loop isolator. Read this article:

http://mysite.verizon.net/vze20h45/radio/radio_pc/radio_pc.html..

This one is also interesting:

http://www.bcae1.com/glisoltr.htm

A commercial product:
http://www.elektronikashop-vdsluis.nl/product_info.php?products..

As you can see there are products commercially available, I ordered one. As soon as it comes, I'll let you know how it works.

So basically a separator transformer (1:1 transfer ratio) between SID output and amplifier/mixer input would do the job. But since an isolator transformer is reversable, it could happen that if a high voltage transient comes from amplifier/mixer side, this is transferred to the SID. So I think that 2 clamping dioes could be put on the coil that goes to the amp/mixer. I will test this also, as I am building an isolator myself.

Commercially available products I think don't have clamping diodes.

More to come......
2008-07-10 17:44
null
Account closed

Registered: Jun 2006
Posts: 645
Quote: Let's put fans in our C64 so they start sounding awful!!!

...but, yes, I think that is pretty much the recieved view on why they added the "cooling stuff" in later models.

@Mogwai: What are your plans? Will it result in a product which people could by, assembled and ready-yo-use?



I've got 2 fans in my C64: one for the VIC-II, and one for the chassis. you barely hear them, only if you really pay attention to it.

these are 2 CPU fans, 12V, but hooked up to 9VAC on the c64 userport.

------------------------------------
http://zomgwtfbbq.info
2008-07-11 22:34
SIDWAVE
Account closed

Registered: Apr 2002
Posts: 2238
put heatsinks on all chips in the c64, that will prolong its life. use metallic heat conducting double sided tape to glue the heatsink to the chips
2008-08-18 07:13
ready.

Registered: Feb 2003
Posts: 441
good suggestion by Rambones! Never thought about the double sided tape.

I tested the ground loop isolator (see links of my previous post) and I am really satisfied with it. Some advantages:

1)With all the equipment ON, when (dis)connecting the plug on the audio amplifier side no glitch is heard and the SID is well protected.

2)Also the two grounds are isolated from each other, thus avoiding the problem of different potentials between them and avoiding the circulation of any current between them.

3)I have alsways had the problem of hearing the 50Hz component from the PSU on my C128DCR. The ground isoloop filters out this components.

I did some reaserch and found a second possibility to protect the SID. This device is an isolation amplifier: hcpl7800, Google for it. It might provide even more protection to the SID, since the previous device is reversable (power may flow from outside to the SID), the hcpl7800 is not reversable, but it requires more components (an operational amplifier and an external power supply).

Ready.
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