MB-6582 Troubleshooting (might need assistance)

Testing/Troubleshooting
1

Finally got around to finishing my MB-6582 baseboard this weekend. Wife was gone ALL DAY, so finally got some man-cave time.

Running into some issues, so I’ve been digging around the forum for testing and troubleshooting advice. I’m outlining my issues below, and will head off to bed. Tommorow, I will start checking the board for errors or issues. Here is what I have so far:

  1. All capacitors are oriented properly.

  2. I will check to ensure I have installed the correct resistors in the right places tomorrow.

  3. Here are the symptoms:

U1_CORE1 - GOOD, currently running MB6582 version of SID app with no issues

U2_SID1 - GOOD

U1_SID1 - GOOD

U1_CORE2 - Two rows of black bars on LCD. When powered on, the following string is sent from the PIC to MIOS Studio:

00000004301268 ms | SysEx: F0 00 00 7E 40 01 01 F7

That’s a good sign!

Was able to upload MIOS v1_9g and Test Tone app without issue. Not sure if the black bars are worth worrying about. However, I did try another PIC (moved U1_CORE3 PIC over to U1_CORE2 socket) and there were no black bars. I could see the text just fine. Maybe I’ll just order a new PIC.

U2_SID2 - No tone on PIN 8 -> PIN 27 test

  • Yes tone on PIN 27 -> U1SID2 PIN 8

  • No tone on PIN 8 -> J23_SID2 Audio Out with 1K Resistor

U1_SID2 - Yes tone on PIN 8 -> PIN 27

  • No tone on PIN 27 -> U2_SID2 PIN 8

  • Yes tone on PIN 8 -> J3_SID2 Audio Out with 1K Resistor

U1_CORE3: GOOD, currently running Test Tone app with no issues

U2_SID3 - No tone on PIN 8 -> PIN 27 test

  • Yes tone on PIN 27 -> U1_SID2 PIN 8

  • No tone on PIN 8 -> J23_SID2 Audio Out with 1K Resistor

U1_SID3 - No tone on PIN 8 -> PIN 27 test

  • Yes tone on PIN 27 -> U1_SID2 PIN 8

  • No tone on PIN 27 -> U2_SID3 PIN 8

  • Yes tone on PIN 8 -> J3_SID2 Audio Out with 1K Resistor

U1_CORE4: GOOD, currently running Test Tone app with no issues

U2_SID4 - No tone on PIN 8 -> PIN 27 test

  • Yes tone on PIN 27 -> U1_SID2 PIN 8

  • No tone on PIN 8 -> J23_SID2 Audio Out with 1K Resistor

U1_SID4 - Yes tone on PIN 8 -> PIN 27 (but not as loud as U1_SID2)

  • No tone on PIN 27 -> U2_SID4 PIN 8

  • Yes tone on PIN 8 -> J3_SID2 Audio Out with 1K Resistor (however it is so low in volume, it is almost inaudible. Had to crank my amplifier all the way to barely hear it)

Any suggestions would be appreciated! I’ll report back my findings on the resistor check and trace check tomorrow.

2

Troubleshooting the first Slave Core/SID section. (CORE_2). Not quite there yet, but getting close.

U2_SID2 Failure: Test Tone App. No tone on PIN 8 -> PIN 27 test.

Trouble Shooting Steps:

  1. Yes tone on PIN 27 -> U1_SID2 PIN 8. Audio Out on U2_SID2 eliminated as an issue.

  2. Interconnections Test:

Uploaded to core successfully, according to MIOS Studio. Still can’t read LCD (black bars).

  1. Noticed that PIC Is warm, other PICS are not warm. Pulled PIC.

  2. CORE_2 Visual Part Check:

R1_CORE2 - Brown/Black/Brown/Gold: 100 ohm Resistor - CHECK. Passes multimeter test. Solder joint looks messy. Resoldered. Retested. Passes test.

R2_CORE2 - Brown/Black/Red/Gold: 1K ohm Resistor - CHECK. Passes multimeter test. Solder joint looks messy. Resoldered. Retested. Passes test.

R12_CORE2 - Brown/Black/Red/Gold: 1K ohm Resistor - CHECK. No read on multimeter. Solder joint looks messy. Resoldered. Retested. Passes test. Multimeter displays proper data.

R10_CORE2 - Brown/Black/Orange/Gold: 10K ohm Resistor - CHECK. Read on multimeter is spotty. Resoldered. Retested. Passes test. Spotty read is gone. Proper data displays.

D1_CORE2 - 1N4148 - CHECK. Multimeter Test: Reads 0.744 one way. No read when poles are switched. Seems the diode is good with no short. Compared to diode in the working Master Core section. Both read the same. Passes test.

C3_CORE4 - Monolithic Capacitor 100nF - CHECK. Not sure how to test. Don’t think my multimeter can test capacitors. Anyone who can provide a tip or trick to test this part?

R9_CORE2 - Brown/Black/Orange/Gold: 10K ohm Resistor - CHECK. No read on multimeter. Resoldered. Retested. Passes test. Multimeter reads now. Proper data displays.

  1. Stopped to check voltages on CORE PIC IC Socket.

IC1:MCLR(1) - IC1:Vss(12) = 5V

IC1:Vdd(11) - IC1:Vss(12) = 5V

IC1:Vdd(32) - IC1:Vss(31) = 0V

IC2(8) - IC2:(5) = 0V

Since Octocoupler is stuffed, not sure if the zero reads are normal or not.

Will continue troubleshooting and report back.

3

UPDATE on Troubleshooting the first Slave Core/SID section. (CORE_2).

Original issue:

U2_SID2 Failure: Test Tone App. No tone on PIN 8 -> PIN 27 test.

As noted in my last post, was able to visually verify all components were correctly installed and resoldered a few bad spots. Board inspection revealed a couple of spots where there might be shorts, and I cleaned them up. However, none of the trouble shooting fixed the original issue

I decided the issue must be with the CORE PIC, itself. I pulled out a spare core - actually the first MIDIbox module I built a couple of years ago! I replaced Slave CORE PIC 1 with this old CORE and SHAZAM. Problem fixed. No more hot CORE PIC. No more black bars on LCD. I successfully uploaded latest version of MIOS and the Test tone app. Successfully tested both U2_SID2 and U1_SID2 with the test tone app.

Now to use the CHANGE ID app and get this pic re-identified.

One issue down, two to go! This is turning into a blog. Maybe I should use the ip.board blog function…

4

I’m calling it quits for this weekend. Everything was going fine with testing Slave CORE 3, then suddenly, the LCD went double-bar on me. I stopped working on CORE 3, and went back to do SID test tone on CORE’s 1 and 2, and now they are dead. Me thinks there is a bigger problem going on, farther back near the power supply. Now I have 2 out of five PIC’s that display the double-bar syndrome. One of them does so in CORE’s 1 and 3, when I swap them.

SO…I’m stopping for a few days and come back with a fresh approach.

5

FWIW I had the same no output/Core problem a few weeks ago and did some posting about it in the SID forum. It was traced to a likely problem of blowing out the Core by touching the wrong pins on the SID socket.