Holton AV800 Schematic

[Kilentra]

Once you have success, the failures won't matter.

 

[Frazzled]

Arrrrrggggghhh!

OK so I replaced the zeners, checked ALL the semiconductors, compared the PCB and schematic until my eyes wouldn't take it and I fired it back up and here is what I got...

Power Supply was only at +/-15.4v

R1 6.62v
R2 6.62v
R3 5.86v
R4 -5.54v

R54 5.47v
R55 .117v
R56 .227v
R57 -5.61v

Crap! Back to the drawing board so to speak.

FRAZZLED

P.S. I never thought my signature would P|$$ me off so much.

 

[thylantyr]

Re: Help!!!

Have you identified R32 on the pcb layout ? It seems to connect
power ground with signal ground.

edit. The old document parts list shows R32 as 10 ohms, 1 watt.
/boo ... This is not on any schematic, old or new... ?? /boo

 

[Frazzled]

Re: Re: Help!!!

Have you identified R32 on the pcb layout ? It seems to connect
power ground with signal ground.

I have R32 installed.
After I made post #67 I figured out that ground and signal ground were escentially the same given R32.

I connected supply ground to point #1 shown in post #67

Thanks!

 

[thylantyr]

Another question. Have you install the jumpers on the pcb ?

He uses resistor pcb footprints where a 'short' is installed. 🙂

 

[Frazzled]

Re: Re: Help!!!

edit. The old document parts list shows R32 as 10 ohms, 1 watt.
/boo ... This is not on any schematic, old or new... ?? /boo

I am looking on page 12 of the new guide and R32 is clearly shown as 10K 1watt, on one of the older schematics it is called R42.

Sheesh!

 

[Frazzled]

Another question. Have you install the jumpers on the pcb ?

He uses resistor pcb footprints where a 'short' is installed. 🙂

YUP, all installed. 🙄

 

[thylantyr]

Post closeup pics so we can check the parts. Maybe another set
of eyes can help............ 😎

 

[Frazzled]

OK

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

 

[Frazzled]

So now it appears I have R32 installed as a 10ohm and not a 10K as the schematic suggests, hmmm

Here is an excerpt from an email I got from Anthony on Sept. 5 2001...

I have checked the schematics and it seems you are right. some how another schematic has slipped in. My apologies!. I will find the right schematic and update the pdf file on the web site ASAP. The parts list however is correct. So you can start constructing the pcb from that in the mean time.

OK, I gotta go look at things again...

 

[thylantyr]

The problem is trying to populate parts when the silkscreen
doesn't match the new AV800 document

Translating the mess is confusing.

I think you have to trace the signals on the pcb and match it up
to the schematic as best you can.

My AV800 pcb is also dated 2001 so we must have the same
boards.

Use the older AV800 document, not the new.

R32 on the pcb requires a 10 ohm resistor.

Double check those Q1, Q2 resistors orientation of ECB.

Is Q8 installed for pre-flight test or not ?

 

[Frazzled]

Re: Re: Help!!!

Have you identified R32 on the pcb layout ? It seems to connect
power ground with signal ground.

edit. The old document parts list shows R32 as 10 ohms, 1 watt.
/boo ... This is not on any schematic, old or new... ?? /boo

Sorry I looked at the schematic and R32 is actually R42 on the silkscreen.

This just gets worse all the time.

 

[Frazzled]

The problem is trying to populate parts when the silkscreen
doesn't match the new AV800 document

Translating the mess is confusing.

So I am finding out, sheesh!

I think you have to trace the signals on the pcb and match it up
to the schematic as best you can.

My AV800 pcb is also dated 2001 so we must have the same
boards.

Use the older AV800 document, not the new.

R32 on the pcb requires a 10 ohm resistor.

Double check those Q1, Q2 resistors orientation of ECB.

OK

Is Q8 installed for pre-flight test or not ?

Yup it sure is.

Frazzled, no really I mean it I am FRAZZLED!

 

[Frazzled]

I took a high res. scan of the silkscreen before I started populating the board, for reference, but I'll be damned if I can remember which CD I burned it to. I am going to try and dig it up.

Just as a curious side note, the last time Anthony posted something on DIY was 02-26-2004 07:23 PM but the last time he was here looking around was 07-20-2004 09:57 PM (30 days ago)

I just wish I knew why he wouldn't like to jump into a thread like this and help out, it's his baby, nobody knows the amp like he does, I paid good $$ for these boards, I spent considerably more buying all the parts, I intended to spend further riches building a nice case for the amp, I have a lot of time and money invested in this project and I feel it could all come together nicely with just a bit of info and help from Anthony. It is all so disappointing. 🙁

 

[thylantyr]

I haven't built my AV800 so you have more experience than me,
but the pre-flight test says not to install Q8.

I was looking at my pcb layout and guess what? I also goofed
on Q1 and Q2, ECB orientation... doh... and I forgot to install that 10
ohm resistor.

Did you twist the ECB leads on the transistor so they fit in
the appropriate holes on the pcb?

Based on my experience with electronics, anytime I goofed
in the installation of parts, sometimes the parts get damaged
so when you connect them up correctly, it doesn't work and
it confuses you more.

If you feel confident that everthing is cool, then I would work
backwards and remove all semiconductors and check them
with a meter to make sure they are fully functional. Sometimes
when you check in circuit you get erroneous readings.

 

[thylantyr]

I'm looking at your screenshots, can you check your R13 because the
color band looks odd, that location should have a 10k 1W resistor,
I see some other value unless my eyesight is bad 🙂

 

[thylantyr]

Silkscreen picture here;

http://home.pacbell.net/lordpk/amplifier/Av800-2.jpg

 

[thylantyr]

I see something else odd on your screenshot.

R31 = 4.3k = good
R30 = 4.7k = good

but

R28, R29 doesn't look like it's 100 ohms. It looks like 47 ohms or
47 something ohms

 

[thylantyr]

Check R40 & R42 on the pcb, should be 10k 1W. I see two 23 ohms
resistors ????

 

[Kilentra]

I don't think it really matters if you install Q8. With this installed you get a small gate driving voltage.. it's mainly used as a tracking voltage reference by Vgs. Without it, don't you get no voltage at all?