A
Arfa Daily
Guest
Anybody got schems for a Denon PMA 255UK or similar model ?
Cheers
Arfa
Cheers
Arfa
Navigation
Install the app
How to install the app on iOS
Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
More options
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
M
Mark Zacharias
Guest
"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:0%s6s.289870$Up5.22351@fx06.am4...
Not finding one...
Mark Z.
news:0%s6s.289870$Up5.22351@fx06.am4...
Anybody got schems for a Denon PMA 255UK or similar model ?
Cheers
Arfa
Not finding one...
Mark Z.
A
Arfa Daily
Guest
"Mark Zacharias" <mark_zacharias@labolgcbs.net> wrote in message
news:505d0656$0$28844$4c5efc6d@fastusenet.org...
ticket "Advise before going ahead" which says that the owner is not going to
want to shell out the amount of labour cost to try and find the problem
without the benefit of schematics. I asked the store that took it in, and
they confirmed that the owner "didn't want to spend a lot" so I will leave
it this coming week in case a schematic comes to light, and then send it
back with an 'inspection only' fee attached ...
Arfa
news:505d0656$0$28844$4c5efc6d@fastusenet.org...
No, I couldn't either. And it's a strange fault, and it says on the job"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:0%s6s.289870$Up5.22351@fx06.am4...
Anybody got schems for a Denon PMA 255UK or similar model ?
Cheers
Arfa
Not finding one...
Mark Z.
ticket "Advise before going ahead" which says that the owner is not going to
want to shell out the amount of labour cost to try and find the problem
without the benefit of schematics. I asked the store that took it in, and
they confirmed that the owner "didn't want to spend a lot" so I will leave
it this coming week in case a schematic comes to light, and then send it
back with an 'inspection only' fee attached ...
Arfa
M
Mark Zacharias
Guest
"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:G0g7s.165$yP5.47@fx25.am4...
What is the general type of unit and the fault? It's an amplifier, yes?
mz
news:G0g7s.165$yP5.47@fx25.am4...
"Mark Zacharias" <mark_zacharias@labolgcbs.net> wrote in message
news:505d0656$0$28844$4c5efc6d@fastusenet.org...
"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:0%s6s.289870$Up5.22351@fx06.am4...
Anybody got schems for a Denon PMA 255UK or similar model ?
Cheers
Arfa
Not finding one...
Mark Z.
No, I couldn't either. And it's a strange fault, and it says on the job
ticket "Advise before going ahead" which says that the owner is not going
to want to shell out the amount of labour cost to try and find the problem
without the benefit of schematics. I asked the store that took it in, and
they confirmed that the owner "didn't want to spend a lot" so I will leave
it this coming week in case a schematic comes to light, and then send it
back with an 'inspection only' fee attached ...
Arfa
What is the general type of unit and the fault? It's an amplifier, yes?
mz
A
Arfa Daily
Guest
"Mark Zacharias" <mark_zacharias@labolgcbs.net> wrote in message
news:505da741$0$29175$4c5efc6d@fastusenet.org...
audio", but actually it does have audio. Problem is that it is 'thin' and
distorted. If you stick a sine wave in, at low levels, it's not far off a
sine wave coming out, but as you wind the wick up, it goes more and more
towards a sort of spiky triangular square wave. Yes, I know that doesn't
make a lot of sense, and is hard to visualize, but then it's also hard to
describe. The drive to the output transistors is the same shape near enough,
so it's pre-output. It's also on both channels exactly the same. At the
volume control and the dual opamp nearby, the waveshape is good. However at
a second opamp closer to the output stage, the distortion first appears.
Both rails are present and balanced at +/- 18v, but both output pins are
sitting at about -12v, and that appears to be the root of the problem. I
tried a replacement opamp just in case, but of course, it was the same. I
find it odd that both channels are the same. About the only thing I can come
up with is the possibility of some fixed bias supply for the stage that is
wrong or missing. With a schematic, it would of course be simple to see what
was going on ...
Arfa
news:505da741$0$29175$4c5efc6d@fastusenet.org...
Yep. It's a fairly 'conventional' discrete amp. The complaint was "no"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:G0g7s.165$yP5.47@fx25.am4...
"Mark Zacharias" <mark_zacharias@labolgcbs.net> wrote in message
news:505d0656$0$28844$4c5efc6d@fastusenet.org...
"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:0%s6s.289870$Up5.22351@fx06.am4...
Anybody got schems for a Denon PMA 255UK or similar model ?
Cheers
Arfa
Not finding one...
Mark Z.
No, I couldn't either. And it's a strange fault, and it says on the job
ticket "Advise before going ahead" which says that the owner is not going
to want to shell out the amount of labour cost to try and find the
problem without the benefit of schematics. I asked the store that took it
in, and they confirmed that the owner "didn't want to spend a lot" so I
will leave it this coming week in case a schematic comes to light, and
then send it back with an 'inspection only' fee attached ...
Arfa
What is the general type of unit and the fault? It's an amplifier, yes?
mz
audio", but actually it does have audio. Problem is that it is 'thin' and
distorted. If you stick a sine wave in, at low levels, it's not far off a
sine wave coming out, but as you wind the wick up, it goes more and more
towards a sort of spiky triangular square wave. Yes, I know that doesn't
make a lot of sense, and is hard to visualize, but then it's also hard to
describe. The drive to the output transistors is the same shape near enough,
so it's pre-output. It's also on both channels exactly the same. At the
volume control and the dual opamp nearby, the waveshape is good. However at
a second opamp closer to the output stage, the distortion first appears.
Both rails are present and balanced at +/- 18v, but both output pins are
sitting at about -12v, and that appears to be the root of the problem. I
tried a replacement opamp just in case, but of course, it was the same. I
find it odd that both channels are the same. About the only thing I can come
up with is the possibility of some fixed bias supply for the stage that is
wrong or missing. With a schematic, it would of course be simple to see what
was going on ...
Arfa