Arcam Alpha 9 amplifier

[TD]

I've had this amp for a long time, around twelve years. The input selector
knob has had an issue for quite some time and I've had enough. Basically the
amp will often cut out one channel, and it can be corrected by twiddling this
selector, sometimes with painful precision needed. Also even though it
doesn't have a push/pull action, pushing on it sometimes helps. I took some
photos which you can see at
http://picasaweb.google.co.uk/Topper.Doggle/ArcamAlpha9.

The input selector is in the bottom left of photo 1, with a close-up in photo
2. It's motorized as it can be moved by remote control. I've tried squirting
switch cleaner through the holes, but no improvement. It appears to be a
sealed unit made by Alps. Is my only option replacement? Can anyone here
tell me anything more than people discussing it at
http://www.avforums.com/forums/arcam-owners-forum/174472-newbie-needs-advice-arcam-delta-290-a.html
and http://www.diyaudio.com/forums/showthread/t-20256.html?

Also, the lid has been off for ages, and I forgot whether the thin foam square
piece goes over the caps as in photo 3 or over the transformer as in photo 4.

Any advice appreciated.

 

[William Sommerwerck]

As this has been a chronic problem, you might throw the warranty of implied
merchantability at Arcam. That is, the quality of the switch is unacceptable
for its intended purpose, and switch -- or even the entire unit -- should be
replaced at no cost to you..

 

[TD]

As this has been a chronic problem, you might throw the warranty of implied
merchantability at Arcam. That is, the quality of the switch is unacceptable
for its intended purpose, and switch -- or even the entire unit -- should be
replaced at no cost to you..

Thanks, but I don't think that after ten years, that argument will wash.

 

[William Sommerwerck]

Thanks, but I don't think that after ten years, that argument will wash.

But that's the point. If you've had this problem over most of the life of
the unit...

 

[N_Cook]

I've had this amp for a long time, around twelve years. The input selector
knob has had an issue for quite some time and I've had enough. Basically the
amp will often cut out one channel, and it can be corrected by twiddling this
selector, sometimes with painful precision needed. Also even though it
doesn't have a push/pull action, pushing on it sometimes helps. I took some
photos which you can see at
http://picasaweb.google.co.uk/Topper.Doggle/ArcamAlpha9.

The input selector is in the bottom left of photo 1, with a close-up in photo
2. It's motorized as it can be moved by remote control. I've tried squirting
switch cleaner through the holes, but no improvement. It appears to be a
sealed unit made by Alps. Is my only option replacement? Can anyone here
tell me anything more than people discussing it at
http://www.avforums.com/forums/arcam-owners-forum/174472-newbie-needs-advice
-arcam-delta-290-a.html
and http://www.diyaudio.com/forums/showthread/t-20256.html?

Also, the lid has been off for ages, and I forgot whether the thin foam square
piece goes over the caps as in photo 3 or over the transformer as in photo 4.

Any advice appreciated.

My wrestling with an Arcam, steer well clear, is the lesson
Long term finecky poor function switch contacts
Motorised switch for R/C use and also manual front panel knob.
I would not fancy desoldering that one by conventional means. No broken pins
or lifted tracks/pads. Desoldered the motor and straightened the bent over
pins while melting solder before hot-airing apart the whole switch
mechanism. Drilled out the copper rivet holding front sub-pannel to pcb,
replaced with nut and bolt. Remove ASIC / PIC IC for safety
All conductors covered in black corrossion, but does all come apart quite
safely, after labelling.
I tested the switches and also that bending the wipers had not produced
trouble with extra back torque and driving round via the motor.
Now its all soldered in, the safety clutch operates in one position, too
much back torque. I had tested before fixing the metal casing back into
place around the switch sections and there must be some sort of additional
strain/misalignment. Took apart to separate the clutch, packing out under
the
2 springs, with hindsight should have had less packing or just one
attended to as now too much pressure.
Position 6, Tape 2, triangle ident is "TDC" down to pcb
and diamond to motor side
Pair of contacts, inside, is between that triangle
and diamond.
If pin 1 is on motor side of each switch wafer
then pin 6 to pin 12(common) in position 6.
The 2 pin wafer has very fine contact pads. This wafer must
be oriented relative to the other 3 so that the dedent action
from the main shaft leaves a bt of leeway to
the 0 side of position 1 and same leeway to 7 side of position 6.
Eventually found the first problem to be the second cog is worn
No broken teeth as such , just frayed/feathered tooth tips , in a very low
torque drive, reduction drive. And the feathering/bunching eventually causes
the gear train to stall.
It is attached, co-axial, to a fine pitch worm drive, with no salvaged
eqivalent around. Turned the worm plus cog assembly around on
the axle and glued a salvaged 1mm pitch cog to the other end.
One possible solution. Fix the whole switchbank rotated 90 degrees, with the
motor uppermost, and bridge ribbon connect the 23 active lines.
Leaving the original hidden underside of the wafers exposed so can add a bit
of relative rotation if required.
Its switching line level signals, so stray signal pickup from extra wire
should be no observable problem.
Check each stage of motor/cog replacement.
Try motor plus first 2 cogs driven from the amp board
before connecting the main shaft etc . All wafers must be in
a valid postion or the remote will not work.
Nedds a good 3V on a DVM The BA6109 is pulsed
and current limited.
If its not possible to find a suitable cog/cogs it
may be possible to turn the worm gear around, fill in
part of the end of the spiral , form a "pulley" in
that and set a rubber band around it.
Cut into part of the junk metal that slides over
carying the main shaft and mopunt a motor and
pulley in a different position.
http://www.diversed.fsnet.co.uk/arcam.jpg
modified Arcam Alps switch/servo mechanism
O is original worn cog, B is bracket, P motor pulley and
A is the Ned Kelly aperture for the drive band.
When first trying out it would not move reliably
to the next dedent position. Because of through
hole plating, or now , the lack of it on the common
line there was a break so not sensing the 1 of 6 posistion.
I increased the size of the motor pulley, from the size
in the pic as the r/c process was timing out going from
1 to 6 or 6 to 1. All the front panel switch shafts
are weak , with the front panel removed. and will easily break.
Final job - heat the Al dome of the control knob
to release from the plastic core, hot melt heated
and reset 1/4 turn around.
IR R/C coding
approx timings, repeat 110mS, 1 bit .83mS, 1 pulse 26uS
ident code 101AB011 then function code
AB=01 or 10 on alternate key presses.
propbably some errors in some of these data, reading off scope display
1/ code 8001, where 8 = 8 repeats of 01
2/ 700101
3/ 600101
4/ 70011
5/ 6001101
6/ 6001011
vol-/ 400110101001
vol+/ 400113
pause (CD)/ 0011010010113

 

[Dave]

I've had this amp for a long time, around twelve years. The input
selector
knob has had an issue for quite some time and I've had enough. Basically
the
amp will often cut out one channel, and it can be corrected by twiddling
this
selector, sometimes with painful precision needed. Also even though it
doesn't have a push/pull action, pushing on it sometimes helps. I took
some
photos which you can see at
http://picasaweb.google.co.uk/Topper.Doggle/ArcamAlpha9.

The input selector is in the bottom left of photo 1, with a close-up in
photo
2. It's motorized as it can be moved by remote control. I've tried
squirting
switch cleaner through the holes, but no improvement. It appears to be a
sealed unit made by Alps. Is my only option replacement? Can anyone here
tell me anything more than people discussing it at
http://www.avforums.com/forums/arcam-owners-forum/174472-newbie-needs-advice-arcam-delta-290-a.html
and http://www.diyaudio.com/forums/showthread/t-20256.html?

Also, the lid has been off for ages, and I forgot whether the thin foam
square
piece goes over the caps as in photo 3 or over the transformer as in photo
4.

Any advice appreciated.

It sounds as though either the contacts in the unit are oxidized or that
they have lost their spring and the switch is just worn out. If the switch
sits in the same position year after year, only a very very tiny amount of
surface area on each contact is actually touching the other contact surface
and is protected from oxidation. So when you go to switch to a particular
setting rather than having let's say half a horizontal mm of area to choose
from you might have a tenth of a mm or less, hence you must painstakingly
find the spot on the switch where the metal is bare. You mention you've
cleaned the switch. You might try having a go with a product called DeOxit
made by a company called Caig. Otherwise I've used other brands from
electronics stores, even Radio Shack sells a variant. I've repaired many
many many products just by properly cleaning up the switches and pots. If
the switch is sealed (or there just aren't access holes to the innards where
you need them), it is quite possible to drill small access holes to the
interior of the switch through which to squirt DeOxit. Use the thin straw
that comes with the can to blast a lot of cleaner in there, then operate the
switch a good 50 times or so. This should remove the oxidation to a degree
that the switch is workable. Next let it dry overnight. The next day spray
with Faderlube or other cleaner/lubricant also sometimes called "tuner
spray". These products contain a small amount of lubricant which will coat
the contacts and prevent their immediate re-oxidation, plus generally
lubricate the works. I find that I generally have to use both products for
any sort of long-term results.

Just a helpful suggestion for next time: when you take photos of your
equipment, use the close-up mode, generally denoted by a flower on the wheel
selector on the camera somelace... otherwise you get blurry photos such as
yours. Also, it's nice to have some tight-in shots of the problem area. As
you neglected to post a shot of the face plate, there's no way for me to
determine which is the problem switch. You might also consider editing the
photo with Adobe Acrobat, or even MS Word or other text editor, to add some
circles, arrows, and relevant text. It just makes it easier for others to
understand your problem and gives you a lot better shot at useful
unit-specific responses.

Dave

 

[Tim Schwartz]

I've had this amp for a long time, around twelve years. The input selector
knob has had an issue for quite some time and I've had enough. Basically the
amp will often cut out one channel, and it can be corrected by twiddling this
selector, sometimes with painful precision needed. Also even though it
doesn't have a push/pull action, pushing on it sometimes helps. I took some
photos which you can see at
http://picasaweb.google.co.uk/Topper.Doggle/ArcamAlpha9.

The input selector is in the bottom left of photo 1, with a close-up in photo
2. It's motorized as it can be moved by remote control. I've tried squirting
switch cleaner through the holes, but no improvement. It appears to be a
sealed unit made by Alps. Is my only option replacement? Can anyone here
tell me anything more than people discussing it at
http://www.avforums.com/forums/arcam-owners-forum/174472-newbie-needs-advice-arcam-delta-290-a.html
and http://www.diyaudio.com/forums/showthread/t-20256.html?

Also, the lid has been off for ages, and I forgot whether the thin foam square
piece goes over the caps as in photo 3 or over the transformer as in photo 4.

Any advice appreciated.

Hello,

This is a fairly common problem on these amps, as well as others
(Creek, Yamaha) that use this Alps switch. Spray cleaning rarely helps
for very long, and taking the switch apart requires lost of patience and
good desoldering, as it must come off the board. Just changing the
switch, if you have a new one on hand is a 1.5 to 2 hour job.

If you use only one input on your amp, then you can use the tape
monitor input as the tape monitor input bypasses the switch.

As to the white square damper, it was originally glued to the underside
of the lid. My suggestion is to throw it away, but you can re-glue it
if you want to.

Regards,
Tim Schwartz
Bristol Electronics