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Checks \ Steps To Do After Recapping ?

Thanks a lot again , I completed the switch board and tried the amp. All is fine , works good.
Tomorrow will start with the power boards and hopefully everything will go good.
I learned a lot from you .
 
Your welcome. What I've learned so far (and still learning) is from reading post here on AK and following Marks Posts as well as Echowars. Even when I don't have the same amp or receiver in question, I still like reading them.

Just be sure to DBT after everyboard.

You should also read your service manual. It tells you how things operate in the amp, etc.

David
 
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Can you please elaborate?
I finished the re-capping of the amp , only the trimmers didn't install.
And the relay , I don't want to replace it now .
 
In the srvice manual I sent you, Page 23 of SM, page 20 on acrobat reader, adjustments. VR1 adjusted full CCW before powering on. I usually do this on DBT as well so to see stability. If you do, don't forget to turn it back down CCW before you plug to wall socket. Not sure if you need to terminate on this amp or not. Mark had instructed me no need to on my 9100, but that is a different amp.

As far as the install, 3 legs, center leg to center hole.
 
Ok , got to the adjustment section , and on the left channel , pins 6 + 12 = I get 45mv
What can cause this , and is this too much ?
 
What all did you change on the amp board? Transistors, diodes, VR1 and caps?
Did you let it warm up and re-adjust?
Do you have a 8ohm resistor load on the a channel?
Are you still on DBT?
Check resistors 16, 17, 18 and 19. Make sure they are with-in spec. Pull one leg and check, no power to amp.
 
Yes these are basically the parts I changed , all according to the list

Power Amp (AWH-051) times two as there
AWH051 C4 22uF 50v CEA 647-UKL1H220MEDANA 22uF
AWH051 C5 330uF 6v CEA 647-UPW1A331MPD 330uF
AWH051 C13 1uF 50v CEANL 667-ECQ-V1H105JL5 1uF
AWH051 q1 2sa798 no-substitute
AWH051 q2 2sc1885 512-KSC1845FTA
AWH051 q3 2sc1885 512-KSC1845FTA
AWH051 q4 2sa912 512-KSA1220AYS
AWH051 q5 2sd358 512-KSC2690AYS
AWH051 q6 2sb528 512-KSA1220AYS
AWH051 d1 1s2473 512-1n4148
AWH051 d2 1s2473 512-1n4148
AWH051 d3 stv-3h no-substitute
AWH051 d4 1s1885 512-uf4004
AWH051 vr1 100 ohms idle current 652-3386H-1-101LF


It's been warmed up for more than 40 minutes
No 8 ohm resistor ... I have a pair of 4 ohm , can I put them together ?

By the way , hooked the amp to my HPM 100's and a source , sounds VERY NICE ! SHARP , EDGY , If I was blindfolded , I wouldn't guess it's a vintage Pioneer (Maybe I'm used to a different sound)
It feels like it's on Steroids !! really!! It's pushy , punchy , high volume...
It feels like it took some Viagra :)
 
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There is a whole procedure to setting dc offset and idle current on an amplifier that has had work done to it.

I have posted them many many time, pages and pages of typing.
(search for markthefixer posts with the word "tease" in them)
Here is a quick thumbnail sketch:

Basically ON THE DIM BULB, the dc offset is set to 0.000v, and the idle current is ATTEMPTED to be set to the correct value - this is to TEASE OUT ANY FAULTS, and it is turned back to minimum before plugging straight into the power line (no dim bulb) because the settings would be too high.

The dim bulb acts like a brownout and presents less than full voltage to the unit. SOMETIMES the protection will NOT click in, because the AC "power line" voltage is reduced too much by the bulb. Then a higher wattage bulb is needed.

After that (with 0.000v set on both channels, and idle on each temporarily turned up, then back down) they are set for real plugged straight into the power line.

The only settings that need an 8 ohm load resistor connected to the speakers is when the spec-4's power limiters are set. This is an SA-8500II, so they are not needed. Nor are the 5.1k ohm resistors needed either - just turn the volume down to no sound....
 
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Which Thermal Paster you recommend me using?
It's for the power boards , 2 transistors on each board...
Also , do you recommend me taking out the output transistors and re-paste them?
 
Correct 4 of each total (in both amps)
Im sorry if I'm missing anything , not because of laziness , because of not knowing!
 
dnpainting said:
You need MT-200 Mica Insulators for these outputs.
type that in on ebay.
Click to expand...

Good start, but it won't fit:

SA-8500ii uses BATWING transistors, which are lots smaller than that 24.5mm hole to hole spacing found on the mt-200 specification.

on the center left there is a batwing transistor sitting on a mt-200 transistor and mica insulator- SEE how much wider the hole is?


IF you use a mt-200 insulator, you will need to punch a hole in the micas, it cannot be drilled. You will need a sharp whitney type hand punch.

edit:
after experimenting with the punch, your best bet is to get some sharp scissors, and cut a strip out of the center of the mica perpendicular to the hole's axis, and butt the two cut edges against each other but not overlapping.

Roper-Whitney-Jr-Sheet-Metal-Hole-Punch-150x150.jpg



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good sil pads in that size, I'd rather go on a quest for hen's teeth.. :D

The mt-200's will be good raw material, I was a bit surprised how well they cut with a sharp scissors. cut the stripe out of the center to being the holes closer together and butt them up against each other. The thermal grease wil tend to hold them in place.

The punching of holes in the mica was a disappointment. It worked, to a point, but if the die is worn on the punch (which anything borrowed will probably be) the hole is quite ragged and needs to be cleaned up with a new razor blade, and then there's the danger of gaps/voids etc created by the punch.

and yeah, I got BUNCHES of those Hong Kong MT-200's, enough that I wasn't reluctant to experiment on one or two.
 
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Hi there . So far the amp is working well after the recap.
One issue I found out today :
Hooked the amp to SPEC 4 , as pre-amp.
Sounds nice BUT - when I turn on the system, the woofers move in an out terribly 2 times! As it sounds "pop" sound from the speakers of course .
Even when sound is set to ZERO.
I hooked the SPEC1 back , to check if its the Sa8500 or the SPEC4 , and it did not do the woofer movement - all fine.
DC on the recapped SA8500 was set according to manual.
Help...

Edit : should I check DC again?
 
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