SPEC-1, Lower output on the right channel

[markthefixer]

with power off for a while, drop the filter and mixing boards through the bottom, inspect them closely for damaged parts. Out of circuit test the transistors (one at a time, no mixing) and ohm test the resistors with one leg lifted.

odds are good you will find the induced damage that way, but the original issue of signal strength is probably a capacitor.

when I go power on for testing, either the boards are all secured in place and buttoned up, or they are on long wires that have them away from the chassis, or in some way out in the open, probably on carpet fragments, and secured from moving. usually i don't if i can possibly avoid it.

 

[markthefixer]

for later reference, I corrected my two post #8 diagrams, and also added capacitors and transistors to it.
later, you will see instances where two capacitors are enclosed in the same box, they are unlikely to be your problem capacitor, because they work together as a pair, one handling the upper half of the waveform, the other handling the lower half of the waveform.

 

[ajohnnyz]

On first inspection of Filter Amplifier Assembly Q4 was crushed sideways, and R14 and R16 looked like they got hot. (picture supplied) So I can see one thing I did. When I pulled the board the first time all was very tight and I bent and shorted Q4 without knowing it.

TESTS:
Q4 - Shorted
Q2 - Shorted
Q1 - OK
Q3 - OK
R14 - 41 ohms - BAD should be 120
R-16 - 43 ohms - BAD should be 120
R13 - 119 ohms
R15 - 120 ohms
R12 - 220 ohms
D4 - 0.63
D2 - 0.62
R10 - 4 ohms
R8 - 217 ohms
R4 - 1 ohms
R6 - 1 ohms
R5 - 1 ohms
R3 - 1 ohms
R7 - 219 ohms
R9 - 4 ohms
D1 - 0.62
D3 - 0.63
R11 - 219 ohms
R13 - 120 ohms
R15 - 120 ohms
C-4 - 35 uf ohms
C1 - 4.1 uf ohms
C3 - 4.3 uf ohms

So it looks like when I pulled the board I bent Q4 and shorted it and it took out 2 transistors and 2 resistors? At this point I don't think any of the pins I talked about before hit?

FYI I have all new CAP's for every CAP on the SPEC-1 in stock if needed. But I don't have any other parts.

And this makes sense so far because the signal coming into the AWM-082 at pins 28 and 30 are perfect, both left and right are the same, yellow is behind the purple (see picture taken before I pulled boards today). I think once I fix these 4 components we will be back to where we were when we started? I hope.

On parts let me know what to order and add anything you think I might need and or should have as shipping is now up to $11 at Mouser, I don't mind having extras components. I realize I will need more parts but I think once these are back in we can start testing the signal again?

 

[markthefixer]

OK, a cap set & no transistors.

a small request, when doing one of your readings reports, could you include the specified value along with your reading?
example:
R13 - (120) 119 ohms
R15 - (120) 120 ohms
makes it a lot easier to run the list.

i see you updated the diode tests.

 

[ajohnnyz]

OK, a cap set & no transistors.

a small request, when doing one of your readings reports, could you include the specified value along with your reading?
example:
R13 - (120) 119 ohms
R15 - (120) 120 ohms
makes it a lot easier to run the list.

we'll have to educate you on diode tests using your dmm.
View attachment 2537846

View attachment 2537842

Ok, I did update some, and I did update my diode tests, I cough that after I did. Refresh your browser.

I just need Part Numbers for some nice new upgraded Transistors and Resistors. This is what I have to learn how to do!!! Caps are easy, But I need to learn how to find the best replacements for other components.

 

[markthefixer]

edit- just read the refresh request, did it and updated the post a bit. moved them to the end for clarity....
and I can't complain about editing posts - I am SOOOOO guilty of that....

we have got to get closer together on these readings dumps... gotta do it now...


and your post, modified:

R14 - (120) 41 ohms - BAD should be 120
R-16 - (120) 43 ohms - BAD should be 120
R13 - (120) 119 ohms
R15 - (120) 120 ohms
R12 - (120) 220 ohms
R10 - (3.9k=3900) 4 ohms uhoh...
R8 - (220k=220,000) 217 ohms uhoh...
R4 - (1k=1000) 1 ohms uhoh... uhoh... uhoh...
R6 - (1m=1,000,000) 1 ohms uhoh... uhoh... uhoh... uhoh...
R5 - (1m=1,000,000) 1 ohms uhoh... uhoh... uhoh... uhoh...
R3 - (1k=1000) 1 ohms uhoh...
R7 - (220k=220,000) 219 ohms uhoh...
R9 - (3.9k=3900) 4 ohms uhoh...
R11 - (220k=220,000) 219 ohms uhoh...
R13 - (120) 120 ohms
R15 - (120) 120 ohms
D4 - 0.63
D2 - 0.62
D1 - 0.62
D3 - 0.63

can you see why I have severe trust issues with your reported readings?

 

[markthefixer]

parts being researched.. I'm not sure if I did a reverse engineering of these transistors & circuits... probably ksc1845's

120 ohm resistors: 660-MF1/4LCT52R121J no, use 660-MF1/4DCT52R1200F

1%, 100ppm @10cents vs 5% 200ppm @13cents and more alternatives from different companies

 

[ajohnnyz]

edit- just read the refresh request, did it and updated the post a bit. moved them to the end for clarity....
and I can't complain about editing posts - I am SOOOOO guilty of that....

we have got to get closer together on these readings dumps... gotta do it now...

View attachment 2537857
and your post, modified:

R14 - (120) 41 ohms - BAD should be 120
R-16 - (120) 43 ohms - BAD should be 120
R13 - (120) 119 ohms
R15 - (120) 120 ohms
R12 - (120) 220 ohms
R10 - (3.9k=3900) 4 ohms uhoh...
R8 - (220k=220,000) 217 ohms uhoh...
R4 - (1k=1000) 1 ohms uhoh... uhoh... uhoh...
R6 - (1m=1,000,000) 1 ohms uhoh... uhoh... uhoh... uhoh...
R5 - (1m=1,000,000) 1 ohms uhoh... uhoh... uhoh... uhoh...
R3 - (1k=1000) 1 ohms uhoh...
R7 - (220k=220,000) 219 ohms uhoh...
R9 - (3.9k=3900) 4 ohms uhoh...
R11 - (220k=220,000) 219 ohms uhoh...
R13 - (120) 120 ohms
R15 - (120) 120 ohms
D4 - 0.63
D2 - 0.62
D1 - 0.62
D3 - 0.63

can you see why I have severe trust issues with your reported readings?

I don't know? I have a Fluke 179. I am sure I only know 1% of what it can do.
Re-reading:
R10 - DMM Reads 3.926 K.
R6 - DMM Reads 1.002 M
I can put that if that's what your asking? sorry I just got done with my Taxes so I was rounding.

 

[ajohnnyz]

And I like being able to edit a post. I work on a post for hours sometimes re-correcting and updating all info. If I couldn't do that there would be 12 posts with just little changes.

 

[ajohnnyz]

thats rounding to a whole new level

 

[ajohnnyz]

Mark, All my updates are usually done by 2PM PST. So yes refresh as I continue updating 1 post until it's done.

I will give more accurate readings with all the info next time, thanks for the heads up.

 

[ajohnnyz]

parts being researched.. I'm not sure if I did a reverse engineering of these transistors & circuits... probably ksc1845's

120 ohm resistors: 660-MF1/4LCT52R121J no, use 660-MF1/4DCT52R1200F

1%, 100ppm @10cents vs 5% 200ppm @13cents and more alternatives from different companies

OK on resistors, 2 - 660-MF1/4DCT52R1200F. Can you finalize the Transistors and how many should I get, having some in stock is fine, there cheap? and anything else? shipping is more then the parts.

 

[markthefixer]

And I like being able to edit a post. I work on a post for hours sometimes re-correcting and updating all info. If I couldn't do that there would be 12 posts with just little changes.

me too.

re: taxes :sympathy:

R10 - DMM Reads 3.926 K.
R6 - DMM Reads 1.002 M

That is music to my eyes!!! And to my brain!!

Transistors will have to be on faith if we're in a rush. Oh crap!! mouser is out of ksc1845's 6/3 earliest.. digikey too.
AK'er EastPoint probably has plenty for sale (pm EastPoint on AK / peace.love.and.music on ebay)

edit fixed EastPoint's name...

 

[ajohnnyz]

me too.

re: taxes :sympathy:

R10 - DMM Reads 3.926 K.
R6 - DMM Reads 1.002 M

That is music to my eyes!!! And to my brain!!

Transistors will have to be on faith if we're in a rush. Oh crap!! mouser is out of ksc1845's 6/3 earliest..

So many things out, and parts of China are shut down again!

 

[ajohnnyz]

me too.

re: taxes :sympathy:

R10 - DMM Reads 3.926 K.
R6 - DMM Reads 1.002 M

That is music to my eyes!!! And to my brain!!

Transistors will have to be on faith if we're in a rush. Oh crap!! mouser is out of ksc1845's 6/3 earliest.. digikey too.
AK'er EastPoint probably has plenty for sale (pm EastPoint on AK / peace.love.and.music on ebay)

edit fixed EastPoint's name...

lots of different listing for these. KSC1845FTA? and one for 2SA992? but I didn't see 2SA912? Please clarify.
ksc1845: Search Result | eBay

I can get 100 660-MF1/4DCT52R1200F on ebay for the same price for 2 and shipping on mouser and it says there from mouser.
Are these fake or what? 100 for the same price as 2 seems the way to go.
Mouser Electronics P/N: 660-MF1/4DCT52R1201F - 100 QTY | eBay

I want to get the parts ordered ASAP..

 

[ajohnnyz]

Mark, I have updated a past post. #36. and you can call me John.

I have to go get my daughter from school and start my evening routine. Talk to you tomorrow. Going to do some Neumann and AKG mic test on the Yamaha piano tonight.

Thanks again, John

 

[markthefixer]

look at the quantity pricing:
660-MF1/4DCT52R1201F
his costs and his markup...

1 @ $0.13
10 $0.11 ea @ $1.10
100 $0.043 ea @ $4.30
500 $0.026 ea @ $13.00
1000 $0.018 ea @ $18.00
2500 $0.017 ea @ $42.50
full reel 5000x
5000 $0.015 ea @ $75.00

I too buy in quantity.

and it's ksa992 for the opposite polarity twin transistor

well, i really effed that one up - and i LOOKED straight at it.
this thread keeps me constantly off balance, rushed and behind the curve.

2sc1885 & 2sa912 and an error in the schematic...

still working on this post.

 

[ajohnnyz]

look at the quantity pricing:
660-MF1/4DCT52R1201F
his costs... his markup...

1 @ $0.13
10 $0.11 ea @ $1.10
100 $0.043 ea @ $4.30
500 $0.026 ea @ $13.00
1000 $0.018 ea @ $18.00
2500 $0.017 ea @ $42.50
full reel 5000x
5000 $0.015 ea @ $75.00

I too buy in quantity.

and it's ksa992 for the opposite polarity twin transistor

Ok Mark I will buy the 660-MF1/4DCT52R1201F. But I still need to find the right transistors.

 

[markthefixer]

get the c1845 & a992 in a bunch
(we;re not supposed to do ebay links)
https://www.ebay.com/itm/125032881391?hash=item1d1c8a5cef:g:QZAAAOSwr9BelzMc

with other sellers (eprey) you run a very very significant risk of (chinese) counterfeits.

 

[ajohnnyz]

get the c1845 & a992 in a bunch
(we;re not supposed to do ebay links)
https://www.ebay.com/itm/125032881391?hash=item1d1c8a5cef:g:QZAAAOSwr9BelzMc

I get it, but you say "ksa992 for the opposite polarity twin transistor" so I am still confused, sorry.