Watch out for this one folks, just warning you'll because i got fooled.
Symptom: No input selction or audio. All you hear is click click when
you crank the volume control.

The BD3816K1 is mounted on a vertical pcb which plugs into 2
connectors on the main board. 1 connector supplies + and - DC along
with data, clk, mute etc, the other connector has 5 channel audio
outputs to main board. A few 8 pin smd op amps lie in the ics
periphery.The vertical board has pcb mounted rca sockets for various
audio inputs. I measured supplies, looked at data and clock on my scope
and everything checked out fine. Two transistors in a TO92 package had
"K429 A1266" and "K435 C3198" printed on them. I wrongly assume
they're FETs and do an in circuit check for a shorted gate-drain, find
none and move ahead. So i invested 25$ in a new BD3816K1 and replaced
the old one. Naturally i'm shocked and desperate when i power up the
set and find the same symptom. I've already quoted estimate and an
anxious knot in my stomach has me thinking "oh god what if another ic
which isn't available locally is the actual culprit , i'm doomed."
I slip into depression , curse the woes of this trade , and decide to
give it a last attempt before resigning myself to accepting another
loss.I look up datasheets for 2sk429 and i find the package doesnt
match, turns out the damn thing's a 2SA1266 with an open BE junction.
The other being a 2SC3198, the K no.s printed on top in both cases.
Seems like some leakage from another device connected to the cd input
on board (it left a nasty scar near the rca socket)( i'll bet a
philips....say what?) took out both the transistors. They are in
series with + and - supplies.
What is this transistor coding system that starts with K ?, have never
seen it before.
Jango

jango2 wrote:
Watch out for this one folks, just warning you'll because i got
fooled. Symptom: No input selction or audio. All you hear is click
click when you crank the volume control.

The BD3816K1 is mounted on a vertical pcb which plugs into 2
connectors on the main board. 1 connector supplies + and - DC along
with data, clk, mute etc, the other connector has 5 channel audio
outputs to main board. A few 8 pin smd op amps lie in the ics
periphery.The vertical board has pcb mounted rca sockets for various
audio inputs. I measured supplies, looked at data and clock on my
scope and everything checked out fine. Two transistors in a TO92
package had "K429 A1266" and "K435 C3198" printed on them. I
wrongly assume they're FETs and do an in circuit check for a shorted
gate-drain, find none and move ahead. So i invested 25$ in a new
BD3816K1 and replaced the old one. Naturally i'm shocked and
desperate when i power up the set and find the same symptom. I've
already quoted estimate and an anxious knot in my stomach has me
thinking "oh god what if another ic which isn't available locally is
the actual culprit , i'm doomed."
I slip into depression , curse the woes of this trade , and decide to
give it a last attempt before resigning myself to accepting another
loss.I look up datasheets for 2sk429 and i find the package doesnt
match, turns out the damn thing's a 2SA1266 with an open BE junction.
The other being a 2SC3198, the K no.s printed on top in both cases.
Seems like some leakage from another device connected to the cd input
on board (it left a nasty scar near the rca socket)( i'll bet a
philips....say what?) took out both the transistors. They are in
series with + and - supplies.
What is this transistor coding system that starts with K ?, have never
seen it before.
Jango

So the A1266 fixed it? The "K" stands for KSA1266 as opposed to 2SA1266.
Korean counterparts, usually but maybe not always interchangeable with the
Japanese.

I've been looking through the service manual for the RX-V350 (US version
anyway...)

Cannot find the transistors you reference.

Mark Z.

Yes, replaced both A1266 and C3198, both had open B-E junctions.Problem
solved!. I think their part designatory numbers were Q451 and Q452 on
the pcb.
So let me get this right, K429 is supposed to be KSA1266? How weird.
Jango

jango2 wrote:
Yes, replaced both A1266 and C3198, both had open B-E
junctions.Problem solved!. I think their part designatory numbers
were Q451 and Q452 on the pcb.
So let me get this right, K429 is supposed to be KSA1266? How weird.
Jango

NO! The K249 would be a 2SK249 FET, I would assume. I was only talking about
the bipolar TO-220 plastic tab ones with the "K" mark at the top.

Mark Z.

Mark D. Zacharias wrote:
jango2 wrote:
Yes, replaced both A1266 and C3198, both had open B-E
junctions.Problem solved!. I think their part designatory numbers
were Q451 and Q452 on the pcb.
So let me get this right, K429 is supposed to be KSA1266? How weird.
Jango

NO! The K249 would be a 2SK249 FET, I would assume. I was only talking about
the bipolar TO-220 plastic tab ones with the "K" mark at the top.

Mark Z.

Firstly, there are just 2 TO92 transistors on the board.
Secondly the numbers printed on them read;
K429
A1266
Just like that, K429 above A1266.
I'm thinking here this might be another one of their ploys to con us,
and then they'd shoot off a bulletin to the glorious authorised service
centre family informing them of the mysterious double printing.
Remember my pioneer trap switch post?.

"I've been looking through the service manual for the RX-V350 (US
version
anyway...)
Cannot find the transistors you reference"

The unit i had was made in China. Did you locate Q451, 452 on the
schematic?
Jango

jango2 wrote:
"I've been looking through the service manual for the RX-V350 (US
version
anyway...)
Cannot find the transistors you reference"

The unit i had was made in China. Did you locate Q451, 452 on the
schematic?
Jango

Yeah, I meant the Yamaha U, C model intended for the American market.
They're all made in China.

I probably should have passed on commenting about the markings on your
transistors - I'm not looking at them after all. I was just relating my
experience with Korean counterparts, and assumed your Yamaha used them,
which would have been pretty common.

Q451 and Q452, in my schematic they are signal transistors used as +
and - 7 volt regulators. Physically near IC451.
They transistor types in my schem are 2SA1015 and 2SC1815.

I had glanced at them before but hadn't looked too closely because they
weren't the larger type regulators that yours seems to have, and for some
reason the "Edit - Find" function of Adobe 7 isn't picking up the schematic
locators on this one.


Mark Z.

jango2 wrote:
Mark D. Zacharias wrote:
jango2 wrote:
Yes, replaced both A1266 and C3198, both had open B-E
junctions.Problem solved!. I think their part designatory numbers
were Q451 and Q452 on the pcb.
So let me get this right, K429 is supposed to be KSA1266? How weird.
Jango

NO! The K249 would be a 2SK249 FET, I would assume. I was only
talking about the bipolar TO-220 plastic tab ones with the "K"
mark at the top.

Mark Z.

Firstly, there are just 2 TO92 transistors on the board.
Secondly the numbers printed on them read;
K429
A1266

Yup - this is the one that got me. The old 2SA1266 is a plastic - tab TO-220
type. Sorry for the mix-up.

Mark Z.