Troubleshooting MB-6582 NO 5V

[highrider]

Hi guys, I thought it was all goodbut apparently I screwed up somewhere.

Here are my readings taken from a red base pcb (from smashTV). The whole pcb is populated with everything apart from the IC's .

Don't get me wrong I followed the instructions carefully and assembled the PSU option A.

j3-0.57

J25-12.73

output of V1 (c12) -8.94

sid socket's (1- 8) - 8.94

Power switch pins

1-0.56

2-0.56

3-0

4-4.72

5-4.72

6-0

I am getting 4.56 and 4.60 from the top two pins on the C64 PSU (with the plug facing you)

I can't find 5v anywhere in the psu section of the pcb and I'm a bit lost here.

If I missed some vital information, please let me know.

Thanks,

V!

Edited January 14, 2010 by highrider

[Wilba]

I'm not sure if you're measuring the 5V correctly out of the plug.

Refer to the PCB layout: http://www.mb6582.org/plans/MB-6582_Base_PCB_R2_Color.pdf

and measure 5V between the "5V" and "GND" pins on J1A (which is under J1, the power socket), J3 and J4

These should all be the same, and the same as the C64 PSU output, since it outputs regulated 5V so the 5V and ground pins are connected directly to the PCB through the power switch.

Since you measured 4.72V on the switch, I'm assuming they'll all show 4.72V and that indicates the PSU isn't that good... it really should be MUCH closer to 5V... like between 4.98V and 5.02V.

Refer to this diagram: http://www.ucapps.de/mbhp/mbhp_8xsid_c64_psu_optimized.pdf

to check the pins of the C64 PSU's plug.... the middle pin is ground, the one next to it is 5V.

Note that some C64 PSU's the 5V will be on the OTHER side of ground than shown in this diagram, but this is handled on the PCB by the track between both pins under the socket.

[highrider]

I'm not sure if you're measuring the 5V correctly out of the plug.

Refer to the PCB layout: http://www.mb6582.org/plans/MB-6582_Base_PCB_R2_Color.pdf

and measure 5V between the "5V" and "GND" pins on J1A (which is under J1, the power socket), J3 and J4

These should all be the same, and the same as the C64 PSU output, since it outputs regulated 5V so the 5V and ground pins are connected directly to the PCB through the power switch.

Since you measured 4.72V on the switch, I'm assuming they'll all show 4.72V and that indicates the PSU isn't that good... it really should be MUCH closer to 5V... like between 4.98V and 5.02V.

Refer to this diagram: http://www.ucapps.de/mbhp/mbhp_8xsid_c64_psu_optimized.pdf

to check the pins of the C64 PSU's plug.... the middle pin is ground, the one next to it is 5V.

Note that some C64 PSU's the 5V will be on the OTHER side of ground than shown in this diagram, but this is handled on the PCB by the track between both pins under the socket.

Ok,

with the power switch in "off" position I'm reading

J1A

1 0.20

2 5.05

3 GND

4 0.32

I took another reading from the switch, with ground being pin 3 of J1A this time (switch off)

S1

1 5.06

2 0

3 0

4 0.30

5 0

6 0

So I assume the PSU is fine unless I should be reading 9v from S1 too. I measured the plug and i'm getting the same 5.06 out of one of the pin's. BTW I have attached a picture of the PSU's plug .The lower two pins ( the ones that are so cosy together) are measuring 5.05V, all other pins give me no V's.

Now with the power on it's a different story.

J1A

1 4.55

2 0.37

3 GND

4 4.72

J3 0.31

J4

5v- No 0.29

9v-Yes . 8.96

12v- 0

So i guess the problem starts at J4. I have soldered the bridge J71 with a resistor leg (that was before I discovered those neat bridges for sil headers), but it should be alright. the soldering joint is stable.

Waiting patiently for a reply,

Many thanks,

Vlad

[highrider]

Just in case.

The C64 PSU i have is a "black brick" type.

it outputs : 5VDC 7.5W 9VAC 6.7VA.

and after a short game of intl. Karate I can confirm that it's working with my C64 ("breadbox" type).

[Wilba]

OK... to start with, you aren't measuring the 9V AC pins correctly... the 9V AC coming out of the C64 brick is independent of the 5V/GND coming out. So the readings of the 9V pins at J1A aren't right and can't be, you're probably measuring DC and also measuring it against ground. If you measure AC between the outer pins of J1A, you'll get 9V.

It doesn't really matter because your 9V DC measurements look OK anyway.

The problem MIGHT BE a missing bridge at J73, which connects the 5V out of S1 to the rest of the 5V tracks on the PCB.

It SEEMS like you have J71 and J72 correct, the common pin of the 7809 is connected to ground, so your 9V AC out of the PSU is being turned into 9V DC relative to the SAME ground as the C64 PSU. Which is PSU Option A... when it's PSU Option B, the 9V DC becomes relative to the +5V supply so you can get 14V to make 12V DC with V3. Basically if you see 9V on J4 then that should mean your 9V regulation is fine.

and thanks for the beer... I would have helped you more anyway, no need to bribe in advance :thumbsup:

[highrider]

you're probably measuring DC and also measuring it against ground. If you measure AC between the outer pins of J1A, you'll get 9V.

That is correct, I'm in the same mode on my multimeter for all the voltage readings because I've got no ******* clue how to operate this thing apart from getting some basic input. Yes, I was measuring against ground. However I have built some devices (mgb midi interface) successfully just by following the schematic and instructions carefully, so I hope with the MB-6582 I have done as well.

Basically if you see 9V on J4 then that should mean your 9V regulation is fine.

It's there and at at the right pins of the SiD IC's it's giving me the correct voltage.

I'm publicly troubleshooting in the forum because I didn't get the right voltages at the PIC sockets. I got those low voltages of 0.30 / 0.27 that I noted in the previous posts instead. If I understand correctly that may be because I'm not measuring them with the right mode on my multimeter. So at the moment I'm guessing that I soldered everything in it's right place (no I'm not that noob, it's the late hours) and if I got the 9V right at J4 I should be fine and the only reason I'm not picking up the 5V at J4 and the PIC sockets is because I'm in the same mode on my multimeter and because I'm measuring them relative to ground?

That jibberish aside I'm really grateful for the feedback man and the beer was never meant as a bribe, I just thought it had to be done, so why not!?

Cheers!

Vlad

[Wilba]

No, you're measuring 5V correctly... pins labelled 5V should be +5V relative to GND pins, everywhere, for all PSU options.

I think you overlooked my solution:

The problem MIGHT BE a missing bridge at J73, which connects the 5V out of S1 to the rest of the 5V tracks on the PCB.

It's the only explanation for 5V at the power socket and power switch and not anywhere else.

[highrider]

No, you're measuring 5V correctly... pins labelled 5V should be +5V relative to GND pins, everywhere, for all PSU options.

I think you overlooked my solution:

The problem MIGHT BE a missing bridge at J73, which connects the 5V out of S1 to the rest of the 5V tracks on the PCB.

It's the only explanation for 5V at the power socket and power switch and not anywhere else.

You were right! Unfortunately I made had to make a mess of the PCB to solder all of the bridges in PSU section but now it's fine and I'm reading 5V and 9V.

Thanks for the help Jason!

Vlad

[highrider]

No, you're measuring 5V correctly... pins labelled 5V should be +5V relative to GND pins, everywhere, for all PSU options.

I think you overlooked my solution:

The problem MIGHT BE a missing bridge at J73, which connects the 5V out of S1 to the rest of the 5V tracks on the PCB.

It's the only explanation for 5V at the power socket and power switch and not anywhere else.

OK, it worked for a bit and than it stopped working. :shocked:

I've located the problem, the patch on all the pin's of J3 and J73 came off due to my poor soldering there is also a damaged track in between the first pins of J3 and J73.

Is there any way I can work around these connections?

Thanks,

[Wilba]

Don't worry about J3, it's only an optional 5V/GND output.

Try soldering a wire between J73 pin 2 (or C3 "+" pin) and J71 pin 1.

Also, to connect 5V to J2 (the header for the power LED), solder wire from C3 "+" pin.

[highrider]

Try soldering a wire between J73 pin 2 (or C3 "+" pin) and J71 pin 1.

Tried both ways (J73 pin 2 (or C3 "+" pin)) it still doesn't give my 5V at J4, but it has increased from 0.26V to 0.56V.

However, I have left all the bridges in place on J71, J72 and J73. Should I take the bridge of at J73?

Also, I'm measuring the same 0.56V at the "+" on C3 relative to ground J4. Could it be that I have destroyed the C3 capacitor?

Finally, I'm getting close to 5V only on pins 4,5 on S1 (4.70V) GND being J4 with the power ON. With the power OFF i can read 5V on pin 1 of S1 again relative to GND of J4.

It's likely that I have damaged the connection on J73 while soldering and desoldering the bridge.

Now I'm really stuck. Can you tell me what I should measure so that we can together establish where the source of the problem is?

Thanks,

Vlad

Edited January 17, 2010 by highrider

[Wilba]

Try adding wires like this picture.... that should bypass any problems with J73 being totally stuffed.

You may not need to do all these connections.

[highrider]

Try adding wires like this picture.... that should bypass any problems with J73 being totally stuffed.

You may not need to do all these connections.

Ok, I will make all the connections in the morning and reply with the results! By J73 being totally stuffed you mean the bridge being removed and all the other bridges for PSU option A remaining intact? I just want to make sure to avoid problems when troubleshooting.

And a big thanks for helping me! I'm already making plans to have someone photograph the process of making the CS. My goal is to make a step by step "do this do that" with an elaborate picture gallery. For someone as unexperienced as me in this field the current CS walkthrough seems a bit daunting (mostly because english is not my first language).

Vlad

Edited January 19, 2010 by highrider

[Wilba]

Ok, I will make all the connections in the morning and reply with the results! By J73 being totally stuffed you mean the bridge being removed and all the other bridges for PSU option A remaining intact? I just want to make sure to avoid problems when troubleshooting.

Yes, you say J73 has damaged pads/tracks and is probably the cause of no 5V after this point, i.e. at J4.

J71 and J72 seem to be good if you are getting 9V at J4. So leave J71 and J72 alone. They are not the problem. Missing 5V at J4 is the problem, and is probably only because of a problem at J73.

Solder wires as shown to connect up the 5V tracks which are not being connected due to J73 being damaged.

The red wires also show what SHOULD be connected by J73 being bridged correctly... i.e. points which should be 5V for PSU option A.

[highrider]

Yes, you say J73 has damaged pads/tracks and is probably the cause of no 5V after this point, i.e. at J4.

J71 and J72 seem to be good if you are getting 9V at J4. So leave J71 and J72 alone. They are not the problem. Missing 5V at J4 is the problem, and is probably only because of a problem at J73.

Solder wires as shown to connect up the 5V tracks which are not being connected due to J73 being damaged.

The red wires also show what SHOULD be connected by J73 being bridged correctly... i.e. points which should be 5V for PSU option A.

I have just rewired it according to the image but I don't still don't have the 5V. Maybe I should try PSU option B?

Cheers!

[Wilba]

No, do not try PSU Option B.

Basically you should have 5V at C3 "+" pin. Right? TEST IT!

Connect this to the other places shown. Maybe you forgot to connect it to C3 "+" pin.

Again I'm assuming the track between the power switch and C3 "+" pin is good. TEST IT!

You need to actually do some troubleshooting for yourself now. If I say "connect a pin with 5V on it to J4" then that means you need to actually solder a wire and test that it is connected, not just report back "no it doesn't work".

Use the continuity tester on your multimeter (or resistance tester) and test which points indicated by the red wires on my diagram are connected (i.e. ~0 ohms) and which are not. Including C3 "+" pin.

[highrider]

No, do not try PSU Option B.

Basically you should have 5V at C3 "+" pin. Right? TEST IT!

Connect this to the other places shown. Maybe you forgot to connect it to C3 "+" pin.

Again I'm assuming the track between the power switch and C3 "+" pin is good. TEST IT!

You need to actually do some troubleshooting for yourself now. If I say "connect a pin with 5V on it to J4" then that means you need to actually solder a wire and test that it is connected, not just report back "no it doesn't work".

Use the continuity tester on your multimeter (or resistance tester) and test which points indicated by the red wires on my diagram are connected (i.e. ~0 ohms) and which are not. Including C3 "+" pin.

Ok, thanks that was really helpful. Now I know how to test continuity with my multimeter, which lead to the problem at C3 + pin. On of the patches came of so i had to scrape of the track (5V rails) and connect it to the eloctrolyte + leg on the sunny side of the PCB with a bit of wire. Also my ground pin for the capacitor at C3 was ****ed so I connected it with a wire to J25. Can I connect it to the neighbouring vacant C13 gnd pin?

The rewiring you suggested earlier solved my problem (or perhaps and more likely the break in connection between the patches at C3) as a result we have 5.05 V reading at J4.

Now that I have the correct voltages throughout the circuit a warm glowing sensation fills the solar are plexus and I feel an enormous sense of wellbeing throughout.

Thanks again for your patience and advice.

Vlad

Edited January 20, 2010 by highrider