Looking for Mentors to fix a DOA CA-800
- Thread starter Yamaha Dean
- Start date
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- yamaha ca-800
Yamaha Dean
New Member
That large capacitor with the shrunken sleeve is history.
petehall347
the brandy coffee man
plot thickens . 8 transistors in firing line . if i am looking at this right .
Yamaha Dean
New Member
Thank you - I have downloaded manual - It's all Greek to me right now... Looking for a step by step analysis
Fusible resistor 680Ω 25ma looks like. Manual is a shitty free down load. R619..
Yamaha Dean
New Member
Yamaha Dean
New Member
This is the bottom of the unit that was requested
Yamaha Dean
New Member
Just burned inside the glass - the glass is OK
Yamaha Dean
New Member
I have never done a resistor, transistor or diode check - trust you can give me the steps to do. thanks
petehall347
the brandy coffee man
seen much worse .
Yeah so have I. But for a rookie needs a good clearly legable schematic. I / we know what to look for..
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
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
Yamaha Dean
New Member
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.
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.
Yamaha Dean
New Member
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
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.,,
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
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