Question about test points on a PCB

[HNKTNK]

When giving voltages at test points, please give only that voltage. Describe other voltages elsewhere.
For example, TP9 is exactly the anode of D110. Not the cathode. TP12 is the emitter of Q120, not inner or outer terminal.
You should be able to mention any test point and we will know the exact point.
When you get DC voltages that seem to change, or drop steadily, check that you are connected to the proper ground for the board you are working on, or use the ground at the main filter caps.

Yeah, honestly I don't really understand exactly where the tp is on the component based off of what I see on the schematic. That's something I need to learn. I'm just trying to give all of the information that I'm seeing. My first post and the title of this is a pretty good indicator of that.

[HNKTNK]

And thanks for the advice on the dropping values. That was confusing me. I'm obviously no amp wiz. I've done some basic work on tube amps that I have, and now I'm just trying to get this one working, which is pretty over my head

[g1]

Ok. For example, TP9 has an arrow that touches a particular line. Everything in a straight line to that point is a direct connection.
So D110 anode, D114 cathode, so on down that straight line to R162, all are points that you could call TP9, including anything directly connected to "A_HI" shown on the left of D110. All would measure zero ohms to each other.

Try to get some stable DC readings on the TP's JM mentioned in post #26, and see his edit about the connector. It could be the cause of your dropping meter readings.

[J M Fahey]

Cool.
problem is we are "somewhere else"; be it 1 floor (or 1 room ) or 10000 miles away is the same, *we* are not there and "you and only you" are our "eyes", so we must all agree very well on what are we talking about.

To make it clear to you Iīll tell you what *one* TP means:
TP9 is:


But ... but ... you are showing me one long zigzagging track, two diodes, one connector, one capacitor and 4 resistors!!!! and 8 solder pads !!!!!
Now I am more confused than before!!!
I put the black meter probe on ground or chassis, but WHERE do I put the red one?
ANYWHERE which is painted green (I forgot to paint one C115 leg).
Voltage is exactly the same anywhere green.
Notice that on every component I painted green *one* leg but none of the others.

Technically the track or wire joining various component legs is called a "Net" and is an essential element of PCB design, it shows "whoīs connected to who", here they call certain Net a TP because itīs useful for diagnostic.

Apply this knowledge to all other TPs, because the idea behind it is the same.

NOTE: some PCBs (notably Fender but many others) add an extra pad in the PCB, put some turret or connector pin and call it TP*** so people goes straight to them to measure, they might even neatly label it TP*** on the silkscreen, but as you saw that is not essential.

I remember one computer magazine, (many moons ago) which among the small ads offered small key sized "Any Key" stickers.
Point is, on many software packages often they include "press any key" ... some users panicked and emailed the Service Dept with the question: "I canīt find the Any Key anywhere on my keyboard

and the answer "just press any key, any d*mned key !!!!" didnīt help, so some entreprising genius sold them with a nice picture showing where could they be applied.

[HNKTNK]

Man, you guys have been really helpful. This has really cleared up a ton of the confusion I was having!