[Maxx134]

I double check again , + pin 238VDC, - pin OVDC, the other 2 pin 110VDC, Thats mean something wrong with the rectifier or connection error?

The issue is that your not supposed to be touching the AC pins when have your tester setting on DC..

Same goes other way.
You really need some brush up on basics so I really suggest having someone to talk in person who is available to see the unit as it is way faster/easier that way..
Based on what you said, the voltages are off after the rectifier.
I keep telling you to read up on last member who has this issue in this thread to learn much on the PSU.
It can't be more than 10 pages back.

 

[klnglim]

The issue is that your not supposed to be touching the AC pins when have your tester setting on DC..

Same goes other way.
You really need some brush up on basics so I really suggest having someone to talk in person who is available to see the unit as it is way faster/easier that way..
Based on what you said, the voltages are off after the rectifier.
I keep telling you to read up on last member who has this issue in this thread to learn much on the PSU.
It can't be more than 10 pages back.

Yes , I have read that many times already. I have checked all the connection for every component, non issue include rectifier, so I decide keep going to try another method
, hard wire most of the component part of this amp, as I know hard wire connection is a big sound improvement.
The place I m using to Mod this amp is my private place, unfortunately nobody has any iidea about the electronic stuff, I have never attend any electronic class or school,
I learned everything by myself without any guidance from anyone else. I like experiment or test try always, that's why my amp picture taken always look a bit different everytime. So far what I have learnt and experienced, I believe myself can make this amp alive and show improvement soon

 

[Maxx134]

Ok so when you get a chance, measure voltages of PSU and post.

 

[klnglim]

Ok so when you get a chance, measure voltages of PSU and post.

Sorry for the late reply as busy on work and study other diy project. About my MK8SE, still wait for some resistors for replacement, I also just found some broken traces inside the PCB board, those damage areas are very tiny and need
a magnifying glass to check carefully. Sure will post after complete fix all those problem and replacecment.

 

[klnglim]

Ok so when you get a chance, measure voltages of PSU and post.

Hi! Massdrop on sale MK6+ & MK8SE
https://www.massdrop.com/buy/little-dot-mkvi-mkviii-se-headphone-amp/talk#discussions

 

[baronbeehive]

Not sure I'm understanding this, I'm just trying to get the amp up and running after various mishaps and upgrades, finally putting in a new ammeter. I've just take some measurements and the 2 terminals are continuous with each other, ie the positive and negative terminals are connected inside the ammeters which is obviously wrong. The result is that the 680ohm resistor pictured is continuous over itself.

I checked the other new ammeter and that is the same, whereas the old one is not continuous, what is up here!!

 

[SonicTrance]

Not sure I'm understanding this, I'm just trying to get the amp up and running after various mishaps and upgrades, finally putting in a new ammeter. I've just take some measurements and the 2 terminals are continuous with each other, ie the positive and negative terminals are connected inside the ammeters which is obviously wrong. The result is that the 680ohm resistor pictured is continuous over itself.



I checked the other new ammeter and that is the same, whereas the old one is not continuous, what is up here!!

Hi baron! Those resistors are .68 ohms, not 680. That’s why they show continuity. Nothing’s wrong.

 

[Maxx134]

I checked the other new ammeter and that is the same, whereas the old one is not continuous, what is up here!!

Aside from the resisitor.
If you're testing continuity,
The new meters would read "continuous", like a very low resistance,
as the meters are basically aa working coil over a magnet.
But the old one that you replace that not work is most probably because it is burn "open" and so it wont read "continuous" (which is low resistance ).

 

[baronbeehive]

Hi baron! Those resistors are .68 ohms, not 680. That’s why they show continuity. Nothing’s wrong.

Ha...…..!!! Thanks Sonic, I think you may have saved me another 6 months of searching..... sometimes you can't see whats right there in front of your eyes LOL. I have the wrong resistor there, .68K, not .68R, don't know quite how that happened, school boy error!

 

[baronbeehive]

Aside from the resisitor.
If you're testing continuity,
The new meters would read "continuous", like a very low resistance,
as the meters are basically aa working coil over a magnet.
But the old one that you replace that not work is most probably because it is burn "open" and so it wont read "continuous" (which is low resistance ).

Yes, that occurred to me so I measured resistance. I made another mistake when I thought that there was a dead terminal on the ammeter. I just remembered what bloodhawk said about there being a resistor in the backlight wire, so that's obviously why I couldn't measure continuity through that wire, probably nothing wrong with the blasted meter after all.

But as a warning to anyone buying new ammeters the new ones I got which displayed continuity across the terminals must be a different batch. Both the new ones showed continuity across the terminals, whereas both old ones didn't. The old meters measured 200 on the board and 300 ohms out of the board, which disagreed with the new ones, therefore I would conclude that the new meters may have different ratings which may vary according to which ones you buy.

 

[baronbeehive]

Looks like HiFiCollective only do 5% tolerance Mills wirewound atm, is that OK for this resistor, (the 0R68 resistor)?

Edit: I'll go for the 5% anyway. 5% might be significant for a lower value resistor such as this one but as far as I can make out all this does is to send the output to the left meter after some parasitics are cleaned out via the red caps on the left channel.

 

[SonicTrance]

Edit: I'll go for the 5% anyway. 5% might be significant for a lower value resistor such as this one but as far as I can make out all this does is to send the output to the left meter after some parasitics are cleaned out via the red caps on the left channel.

The meter actually measures the voltage drop across the .68R resistor and displays it in mA. I'm sure 5% is fine though.

 

[klnglim]

Ok so when you get a chance, measure voltages of PSU and post.

Hi there! It's been a long time as I m busy, how are u? Finally I just finished put all the parts inside the board.but no luck as the amp smoke come out from resistor which make me confusing again about what went wrong?
When I began to turn it on, left meter light up and everything look fine. However, when 2nd light from right meter start to turn on till max, the smoke come out from the resistor (red arrow from picture below), the left side meter reverse back to zero and right side meter straight to maximum,
I turn off the amp immediately.
At this moment, I need some advise and help which from your experience,I have no idea why the amp still cant turn on like normal, also can u draw the circle from the picture below where should I take the voltage reading?
I'll appreciate if u can tell me about what I need to do next, so the amp can be fixed?
Thanks a Lot and hope to hear from u soon.

 

[baronbeehive]

Hi there! It's been a long time as I m busy, how are u? Finally I just finished put all the parts inside the board.but no luck as the amp smoke come out from resistor which make me confusing again about what went wrong?
When I began to turn it on, left meter light up and everything look fine. However, when 2nd light from right meter start to turn on till max, the smoke come out from the resistor (red arrow from picture below), the left side meter reverse back to zero and right side meter straight to maximum,
I turn off the amp immediately.
At this moment, I need some advise and help which from your experience,I have no idea why the amp still cant turn on like normal, also can u draw the circle from the picture below where should I take the voltage reading?
I'll appreciate if u can tell me about what I need to do next, so the amp can be fixed?
Thanks a Lot and hope to hear from u soon.

Hi kiglim!Good work so far, don't give up now looks like you're nearly there. Your work looks OK. I'm assuming you've gone through the usual checklist, continuity, resistor values, wires checks, parts positions soldering etc. I don't need to tell you this now, you're probably way ahead of me after all you've done.

I'm hoping to get mine up and running again this week but need to go to an engineer to solder a wire back on the ammeter terminal, my soldering iron is not powerful enough for that job. But one resistor which was incorrect caused a problem so make sure you haven't made any stupid mistakes like me LOL. I also had a cap leg break off unkown to me at the time.

I can't advise you so wait for someone that can.
.

 

[klnglim]

Hi kiglim!Good work so far, don't give up now looks like you're nearly there. Your work looks OK. I'm assuming you've gone through the usual checklist, continuity, resistor values, wires checks, parts positions soldering etc. I don't need to tell you this now, you're probably way ahead of me after all you've done.

I'm hoping to get mine up and running again this week but need to go to an engineer to solder a wire back on the ammeter terminal, my soldering iron is not powerful enough for that job. But one resistor which was incorrect caused a problem so make sure you haven't made any stupid mistakes like me LOL. I also had a cap leg break off unkown to me at the time.

I can't advise you so wait for someone that can.
.

Just found one caps problem and replaced, then try to on again, however bad luck still, this time another resistor smoke (Red arrow from picture below), so have to turn off immediately.