Blown up the floppy drive connection?

[muppets5]

I'm gonna make a fool out of myself overhere...... I bought 2 VIC-20's. Both came with their own power supplies. I ordered a new one to protect my VIC's against old age. But I did not protect them from my own mistakes... I tried to put the PSU cord into the floppy drive connector. And now on one of my VIC's the SD2IEC is not found. On the other it works great. 

 

Is there a way to repair the connection? 

[bluejay]

You can’t plug in the power supply into the serial port (that the floppy drive uses) nor the video output port which is right next to it. It physically will not fit. 
 

So it’s definitely some other issue. I would say replacing the 6522s would be a good start.

 

”Connections” don’t “blow” and you can’t “repair” them.

[+OLD CS1]

9 hours ago, muppets5 said:

I tried to put the PSU cord into the floppy drive connector.

Either you are trolling or you jammed that shit in like parking a tractor trailer in my two-car garage.

 

On a serious note, it is possible the VICs are victims of old age, already, and need the VIAs checked out.

[DistantStar001]

A more likely possibility is that when you tried to insert the power plug into the serial port, you cracked the solder joints to the port on the board.  I'm assuming that these are the "cost reduced" versions that used the same PSU as the C64.  If you had managed to insert the din connector (assuming that you could get it to fit and it was plugged in at the time) then you would have fed both 5v DC and 9 AC currents into the board (from the orientation of the two ports, the 9v AC would have gone directly into the data-line), likely frying every chip in the computer.  There is literally no pin on that port that could take either of those voltages.  As such, the fact that your VIC is booting at all means that this didn't happen, and you likely haven't done any serious damage to the board itself.  I'm also assuming that the port itself is still intact since you've managed to insert a proper serial device after your little mess-up.  My suggestion would be to take the motherboard out (you'll likely have to remove the RF shield from the bottom) and reflow the solder on the port, maybe add a bit more to be safe, then test again. 

 

If it still doesn't work after that, then look into replacing the two 6522 VIAs.  

Edited July 27, 2021 by DistantStar001

[carlsson]

I have a friend who claims she is fully capable of inserting the power cable into either of the two back ports. I have called her out on that but apparently she has a grip of steel when it comes to shoving in cables in the wrong holes.

[muppets5]

For all you non-believers...... I really managed to get it in. Hence I started with the message that I was going to make a fool out of myself here. Carlsson's friend and me share a unique ability. 

 

I am going to look at the solder joints and going to look into what 6522 VIA's are ? Thanks everyone!

[bluejay]

It is quite literally impossible to plug the thing into the serial port. Impossible. Period. I don’t know what made you think it went in, but that isn’t the problem here.

 

The 6522s (VIA; Versatile Interface Adapter) are chips that control lots of different things (hence its name) in the VIC, one of which is the serial port. Failure of the chip (which is common) is a very likely cause of a nonfunctional serial port. The chips were used in countless computers over the years, so replacements are easy to come by.

 

If the chips are socketed, you could easily try and swap the two around and see if that makes a difference. I don’t think both of them are needed for the serial port to work? In any case, you should still buy a couple replacements and stick them in and see if that fixes it. 

[muppets5]

40 minutes ago, bluejay said:

If the chips are socketed, you could easily try and swap the two around and see if that makes a difference. I don’t think both of them are needed for the serial port to work? In any case, you should still buy a couple replacements and stick them in and see if that fixes it. 

Thanks for the explanation. I just got the motherboard out to solder the joints like DistantStar001 suggested. Added some fresh solder too. That did not help unfortunately.  So what's left is to look at the 6522 chips. Mines are soldered on. And those are way above my skillset. Too small. I will try to find someone on a local marketplace if it can be done for a reasonable price. Maybe somebody here is from the Netherlands and knows somebody?

[carlsson]

The 6-pin IEC connector should be almost impossible to mate with the 7-pin 270 degree power connector. The 8-pin 262 degree video connector might be possible to mate with the power connector if the two top pins are pushed outwards quite a bit, turning the 270 degree connector into a 262 degree one. But it takes violence or an already molested connector, it does.

 

(I just tested on a C64C)

 

Edit: I just realized you mentioned VIC-20, not C64. That is even harder, as the VIC only has a 5-pin video connector so the top two pins have nowhere to go. That is unless you have a power supply that only outputs 5VDC, no 9VAC pins.

Edited July 27, 2021 by carlsson

[+OLD CS1]

7 hours ago, muppets5 said:

For all you non-believers.

Oh, I believe you.  I knew a guy who managed to get a PS/2 keyboard plugged into an S-Video port.  You just have a super power I would never want.

 

4 hours ago, muppets5 said:

So what's left is to look at the 6522 chips. Mines are soldered on. And those are way above my skillset.

If you can get hold of 6522s, you can piggy back them then determine if someone needs to help you out with replacing.  Is there any other logic on the VIC-20 between the serial port and the VIA which could have popped?

 

I, however, would not bother.  I would take the one working machine and use it, keeping the problem one for parts or get it to someone who can fix or use it.

[DistantStar001]

So I've looked into this a little more, and I've come up with three possibilities.  

 

First, it could still be the port.  Inserting the power cable into the serial port would have caused several of the pins to go in at odd angles.  It's possible that this might have dislodged the contacts in the port.  If so, the port will need to be replaced.  The only way I can think to test this is with a known good serial cable (or an unsoldered 6 pin DIN) that you can insert into the port. You'll need a multimeter set to continuity to see if the pins on the cable (or DIN) are making proper contact to the solder joints on the bottom of the board.

 

Second, is the 7406 buffer chip.  In circuit, it sits between the VIA and the serial port and has been known to cause device recognition errors when it fails.  Unfortunately, this is almost always soldered in, and will need to be extracted for a replacement.  The good news is that it is a relatively common part and pretty cheap to replace.

 

The last is the 6522 VIAs mentioned before.

 

The good news is that there seems to a way of testing if it's the 7406 or the VIA.  Apparently, the same VIA that controls the keyboard also controls the serial port.  As such, (and assuming your port is good) if all your keys function then the malfunction is likely the 7406 buffer chip, otherwise, it's the VIA.

[bluejay]

8 hours ago, OLD CS1 said:

Oh, I believe you.  I knew a guy who managed to get a PS/2 keyboard plugged into an S-Video port.  You just have a super power I would never want.

Kind of unrelated but are you sure it wasn’t an ADB keyboard? Those have connectors that exactly match S-Video ports. 

[+OLD CS1]

41 minutes ago, bluejay said:

Kind of unrelated but are you sure it wasn’t an ADB keyboard? Those have connectors that exactly match S-Video ports. 

No.  It was a PS/2 which does not match the S-Video port, which is what made the event noteworthy.

[bluejay]

24 minutes ago, OLD CS1 said:

No.  It was a PS/2 which does not match the S-Video port, which is what made the event noteworthy.

Oh. Well, I guess this superpower of plugging stuff into impossible holes does really exist…