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over heating Arcam Alpha 5 CD...

J

jonnoshore

physicist, engineer and healer
I took my faulty AA5 to pieces last night...

There is a blow capacitor on the main board... and some fluid on the board around it and the fuse protector was slightly melted an inch away.

I have the lid and the rear panel off...

How do I lift the main board enough to get under the cap... The Capacitor is C415 near the rear power socket. This must be the source of the over heating..

There seems to be 4 screws around the transformer. and two plastic clip things on the board. The audio board was easy to remove...

All good fun...

The Player was not standard... There is a Trichord clock 2 chippy thing on the audio board and the standard clock chip and a couple of caps / resistors are missing around the 7220 chip...

PS I have the service manual and read a bit of that in it tell me how to get the board off... Next week I will print it out for use at Home...
 
C415 should be a 470n film cap, now C416is an electrolytic 470uf [voltage not shown] but its on a 5v line.

The manual suggests you

remove the four screws near the trans
slide the tray out
remove the2 screws on the mains input
squeeze the 2 pcb pillars

the whole should now lift out

Hope this helps

Ifyou need a copy of the service manuel pm me
 
hi,
Zanash suggests that you slide the draw forward, when you do it reveals a screw down in the plastic in the middle rear of the tray holder.
Another one in the middle of the metal front frame from the inside
securing the front panel and 4 screws at the sides.

you have mail....
dogrun.gif
 
hi John,
unless your 5 is a very different beast to my plus then yours has been got at.
Now you've seen how easy it is to remove the audio board why not contact Zanash and ron for some very cheap mods like wot I have done.
I think that clock has to be ditched though as when modded you don't need to add an external clock.

dogrun.gif
 
By triclock or Trichord... the original clock is not on the board... That may be the problem... :-(
 
The board underneath looks like an older Trichord clock, hence the reason the original clock bits are missing - the Trichord takes their place.

Andy.
 
I'm in the throes of replacing some fried components on the motherboard, Q404, C416 and R415. The cause was a mains plug that became semi-detached and presumably arced away over time. The centre lead of the trannie has vaporised!

Is there a consensus over the optimum output coupling cap?
 
hi Rusty,
Regarding the output coupling caps.
I tried a 100 uf blackgate N type with good results.
ron then sent me a 1uf evox to try, better.
Then I remembered that I had two spare 1uf PCR's (Evox) left from my Hood pre amp kit.
I put these in and the sound became "finished off, polished, sophicticated sound with impact even at low sound levels.
These will be staying in fact once I've installed Andy's super reg then I've finished modding.
In my Arcam I have only the coupling cap between the opamp output and the phono socket with one resistor from output to neg all transistors have been removed from this area along with the two resistors after the coupling caps. There is just no need for them.
I found that the wire from the cap to the phono was critical. I tried silver wire but it had an "edge" to it. I finally settled on a lead out wire from a good quality resistor which sounded neutral.

no resistor.jpg


apologies for the drawing, Alyson said it resembles a man with an erection waiting for a bus?????

....
dogrun.gif
 
Originally posted by john & Jake
no resistor.jpg

apologies for the drawing, Alyson said it resembles a man with an erection waiting for a bus?????
dogrun.gif
Click to expand...

And the little C13 looks like a little sitting dog... Hey it's John and Jake!

Not sure what you are excited about though...
Are you a bus spotter? ;)
 
hi omers,
you'll note the reference to the different sound caused by just a simple change if material in a short length of wire.
This highlights a very important point that can't be stressed enough.
When modding, the player has to be modded within the system it is going to be used in.
Changes can then be added or taken away.
When using a player modded within a third parties system it may not perform as intented when put into the new owners system.
My player has been modified until I am now happy with it when using Exposure amps using my ears as judges.
Put into a N**M system it would sound totally different and need re-modding to sound right.
...
dogrun.gif
 
hi Rusty,
if you modify this area, unsolder the phono sockets from the board and fit teflon or other good quality phono's to the rear panel.
No drilling, the holes are plenty big enough.
....
dogrun.gif
 
Originally posted by john & Jake
hi Rusty,
if you modify this area, unsolder the phono sockets from the board and fit teflon or other good quality phono's to the rear panel.
Click to expand...

I was planning to remove the connection completely and have a pair of flying leads out the back of the CD player... Maybe with a pair of bullets on the end.

QUESTION:

Does Capacitor C415 effect the sound quality?

It was a black Rubycon... I plan to replace it with a Silmic (or something...) the 'new' cap is larger (about x2)...

Are other components likely to be 'shot', how do I tell.

ie.
1. Did another component go which caused the cap to pop?
2. Would another component go pop due to the cap popping?
3. Or would the cap just pop on its own and everything else will be wonderful when replaced?

fellow AA5 diyer's views would be welcome...
 
Now seems to work without distorting... ;-)

Nice. An AA5 for £10 not bad.

Just need to start investigating mods now...
 
John,

My one came with panel mount sockets; I would have changed them anyway, as PCB mount phonos as beloved by Euro manufacturers even on pricy gear are a pet hate.

If one removed the dig out too,one could thread a cable through the hole for an ext PSU for the DAC board, which would also then need some additional support.

I fired mine up after replacing the fried comps, but it only worked briefly before a static-like distortion started, and then complete distortion and no music. Obvciously something is failing as it warms up. Time to let an expert at it I think.
 
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