Looking for Mentors to fix a DOA CA-800

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Fusible resistor 680Ω 25ma looks like. Manual is a shitty free down load. R619..
 
The CA-1000 SM is very similiar to the CA-800, I used it during a CA-800 refurb, saved my eye sight.

At least 2 stressed caps on the power supply/relay board, however damage appears on the power amp boards.
Diode test transistors/diodes there. Need analysis why resistors burnt...

Diode testing of transistors, in a nutshell, c/- markthefixer
DiodeTest.JPG
 
Left power amp
C604 (bipolar) stressed
+/-B supply fuses missing.
R619 toast, 680 ohm FR (on mine at least)

TR606 on heat sink must be suspect along with TR607

Diode check
TR606,7
D601
TR608,609,610,611
 
I have been out working thanks for the info - Can you point to a video how to test for what you want me to do please? I'm very much a Newbie
 
Sorry, no videos, old skool.

First do not power on the amp unless an AK member tells you.

Hopefully you will have a multimeter, it should have a diode test function, look for the diode symbol.
You should have the CA-800 service manual, suggest download the CA-1000 service manual, it's better quality and very similiar.

Diode check
TR606,7
D601
TR608,609,610,611
using the graphic in post 32, the RED/BLACK refer to multimeter probe orientation.
Two results are expected, either 650mV(550-750mV or so...) and OL/Open Circuit.
You will need to download the transistor datasheet to identify the pins emitter/collector/base, many tools, try this one
http://www.alldatasheet.com/

Also, you will doing the test with the transistors still in circuit, this is not preferred but for a first attempt we will try.
 
Very grateful for the information - I'n thinking of buying this for the project - Can you give me your thoughts please - I need simple stupid?
Tekpower TP8260L Analog Multimeter With Back Light, and Transistor Checking dock
 
Analogue meters are cute but I think you would tire quickly
with reading the scale, compared to the digital readout.
Would be good to have hfe, C and L measurement. Maybe a basic MM
and a tester unit, something like the Amazon Etekcity MSR-R500.
Includes 200mV scale for setting bias. It's a cheap MM with
cheap probes, hundreds like it, pick one...

For a tester maybe,
https://www.ebay.com.au/itm/Mega328...518996&hash=item33dee770fc:g:sAEAAOSwmNxaTvc1
has the "latest" SW for auto pnp/npn.,,
 
Build yourself a Dim Bulb Tester, it's a current limiting device, used when first time powering up after rework.
Plenty of plans on AK site.

The CA-800 is a tough rebuild, but worth the effort.

Should you see any of the following on the kerbside then pick them up,
CA-1000, same mechanics as CA-800, better sound
CA-1010, 2010, arguably better again, easier rebuild
Kenwood KA-7100, Marantz 1060 nice "entry level", reasonably easy rebuild
Yamaha pre amps, power amps and about 1000 others
 
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