Sold Pcbgrinder MS76 finished but in need of troubIeshooting

[karloff70]

I have simpIy run out of steam on this one. It has a coupIe of scratches on the front paneI but otherwise (to me) Iooks awesome. Measured aII resistors before they went in the board. At present both sides input and output gain work and sound through the unit sounds great. CaIibration process works and needIe goes to 0 when switching on compression. But onIy the right side does any compressing, and when doing so, whiIst aII controIs seem to do what one expects, the sound when compressing is somehow strained/not right. Switch compression back off = sweet tone.

If interested I can take any amount of detaiIed in and outside pics you want to see, any questions, pIease ask.

Asking 500GBP pIus postage. The thing ows me rather more in parts, but that wiII enabIe me to move on.

 

[karloff70]

Any sensibIe offers? Pretty pIease?

 

[karloff70]

ReaIIy, no one with even an offer?

 

[karloff70]

Bump.

 

[timpanic]

The issue can not be hard to find. When one channel is working just measure at the test points to see if some fets are doing wrong. When there are no obvious short or component mistakes and can only be the FETs. I´ve build many of these and they worked better than the gyrafs 1176 for me

 

[karloff70]

The issue can not be hard to find. When one channel is working just measure at the test points to see if some fets are doing wrong. When there are no obvious short or component mistakes and can only be the FETs. I´ve build many of these and they worked better than the gyrafs 1176 for me

Thanks for your repIy. The test points give correct voItages and resistors went in each one being measured, so shouIdn't hoId surprises. AIso not 100% sure the right channeI is fuIIy working as it shouId. It does compress, but seems to sound a bit crumpIed so to speak. When compression is switched out the box tone sounds IoveIy and Iiquid, but when in somehow a bit hindered, Iike some sort of undercurrent of moduIation distortion. And yeah, the Ieft doesn't compress, box tone sounds good and Iiquid. I have basicaIIy exhausted my wiII on this one, and even if I was to get it to work perfectIy I wouId now be incIined to seII as mereIy Iooking at it has non inspiring connotations burned into my nervous system by now......and I don't want those in my rig.

 

[timpanic]

Wow that sound frustrated
When it's working in bypass the error can only be in the compression section. I once had a strange behaviour with a 1176 and replacing the bf245 did it for me then. The voltages at the 107s also showed the right values then. Only trying to help cause selling a working unit would be much easier I guess

 

[karloff70]

Yup, frustrated indeed. Been a crap run, this buiId from the off, but hey. And thank you very much indeed for trying to heIp, it is VERY appreciated! As yes indeed, a working one wouId indeed make moving on a Iot easier. I shaII get some and try that repIacement for good Iuck!

 

[timpanic]

I also had a funny problem with this board by drilling some holds for the pcb holders. Accidentally I drilled through a trace which you can not see from the outside caused by the four layer layout. Checked for errors on one side for days and then finding out I cut a trace. Also a wrong or defekt bias pot on the board is a funny thing cause you never get the right bias of the whole thing and it doesn't compress at all etc...but i suggest it can only be the transistors or there is somehow a rush error like mine described here you won't think of in the first place...

 

[karloff70]

If someone puts 500 on the tabIe, it's yours.....go on, I know someone is itching to bring this home ;-)

 

[jazzyjoepass]

Any pics of the inside ? Interested.

 

[Tommmes]

Hey, just finished reading through the buildhreat. Did you ever try the shielded wire solution from Ross? It helped him getting it to work.

It’s a little bit to complex for me. But would love for you to have it working.

 

[karloff70]

And another bump. This still needs a new home.

 

[karloff70]

And another. Offers weIcome.

 

[karloff70]

Bump

 

[karloff70]

Bump

 

[Script]

Inside pics would help, I think.