Needing a 1970's Yamaha Engineer (employed by Yamaha)

Why not tell us what it's for. Someone may have experience.
The Yamaha Schematic contain these charts (well most of them)

1663120980748.png


1663121305392.png


1663121391522.png


There is no consistency to the charts from model to model as shown above.
Some charts list a Parts Name that no one can identify or explain what the characteristics are.
 
1. Are you confused?
2. You want to duplicate or repair a Yamaha product?
3. If repair, well, a look at the part will tell you what it is.
4. And also, if repair, state your model, device description and problem, alternately a search will find that the problem has been already resolved, 1970s means 50 years or so ago.
5. Try finding a CA3042, for example.

Good luck....
 
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Ok, post the actual schematic worrying you and put a tick mark (say small red or any visible colour) dot by any doubtful part.
Based on how Yamaha labelled it and your charts we can make a pretty well educated guess about its type.
In fact, which is the chart matching your actual schematic?
You show quite a few,obviously copied from different places, they can´t all be on the same sheet.
Forget what´s used in other schematics.
 
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Ex-Akai tech here. What is the question exactly? If we can identify the part types as found on the boards? We can but then you need to indicate which parts you don't recognize.

BTW you seem to replace some part types for other part types. Are you sure it makes sense to have others people explain what type the parts are when you replace them for different types anyway?
 
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Ex-Akai tech here. What is the question exactly? If we can identify the part types as found on the boards? We can but then you need to indicate which parts you don't recognize.

BTW you seem to replace some part types for other part types. Are you sure it makes sense to have others people explain what type the parts are when you replace them for different types anyway?
It is not intentional to change part types with incompatible types. This is my primary reason for asking assistance.
 
Self quoting:
Ok, post the actual schematic worrying you
check.
and put a tick mark (say small red or any visible colour) dot by any doubtful part.
Please do.

Side note: the first schematic (full amp) is barely readable, if at all.

The second one scale is what we need, so when you ask bout any specific part, make that section big enough.

Side note 2: on the readable schematic
1663131127186-png.1090657

MOST of the parts (>90%) do not have any extra symbols at all.

The very few which do, use the square, triangle or double circle (to assign them a name); respectively:
  • cement resistor
  • metal oxide resistor
  • Mylar capacitor

clearly indicated in the charts, not sure what your doubt is.

If you are baffled because exact same part is alternatively called "metal oxide resistor - metallized oxidation resistor - metal oxide - metal oxide film resistor" , they are all one and the same.
Chalk it to translation into an indoeuropean syllabic alphabet from an originally Chinese ideographic one.
There is not a 1:1 equivalence, by definition, except by sheer chance.

But any tech will read those codes with no problem.
 
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Self quoting:

check.

Please do.

Side note: the first schematic (full amp) is barely readable, if at all.

The second one scale is what we need, so when you ask bout any specific part, make that section big enough.

Side note 2: on the readable schematic
1663131127186-png.1090657

MOST of the parts (>90%) do not have any extra symbols at all.

The very few which do, use the square, triangle or double circle (to assign them a name); respectively:
  • cement resistor
  • metal oxide resistor
  • Mylar capacitor

clearly indicated in the charts, not sure what your doubt is.

If you are baffled because exact same part is alternatively called "metal oxide resistor - metallized oxidation resistor - metal oxide - metal oxide film resistor" , they are all one and the same.
Chalk it to translation into an indoeuropean syllabic alphabet from an originally Chinese ideographic one.
There is not a 1:1 equivalence, by definition, except by sheer chance.

But any tech will read those codes with no problem.
Cement Resistor vs Cement Molded Resistor?
Metal Plate Resistor?
Fire Proof Resistor?
Aluminum Electrolytic "Z" Type?
SBL Film?
MS?
UPF?
Carbon Film vs Fireproof Carbon Film?
Semiconductive Ceramic?