Modded A850HD

[lincsat]

Have you maybe got them mixed up? I just had a look at mine and it has a 10ohm resistor in the R6 position (As in brown, black, black).

My power board is a 2011 one so I'm guessing it's not new.

Or do you mean the difference between the 750 and 850 boards?

2013 board = Brown, Black, Black, Gold - 2011 board = Yellow, Violet, Orange, Gold. I'm not saying that is definitely the mod, I'm saying it's the only difference that I can see.

[Scotster]

2013 board = Brown, Black, Black, Gold - 2011 board = Yellow, Violet, Orange, Gold. I'm not saying that is definitely the mod, I'm saying it's the only difference that I can see.

Quite strange that. Maybe mine had the "mod" before the "mod" was released .

[TheCoder]

I have boxes with the "new" board, looking at the PSU, the only difference I can see is 1 resistor (R6) is 10 ohm on the new board and 47 Kohm on the old board. In any case, when tested here, the "new" boxes perform exactly the same as the "old" boxes.

hmm, that doesn't sound like the tuner psu filter mod. Afaik, that consisted of changing the positioning of a resistor within the rc filter circuitry. The component layout may be identical on both versions of circuit board (not seen the new one yet) but if thats the case then their will be a subtle tracking difference.

Not sure what the resistor value change is all about but I wouldn't go replacing 47k's with 10R on a switcher without knowing exactly what I was doing and why I was doing it

[TheCoder]

The point I was making is that I believe there was always a fault with the boards and that the change to 256 only made things worse. I don't think the switchover was the cause of the hassle, it was always there..... 256 just made things worse.

I've been told the circuitry for the tuner psu was that recommended by the tuner manufacturer but that they have now discovered that the UK requires a slight tweak due to VM running with 'non standard' signal levels within some of the franchise areas. By the sounds of it, all the mod does is add an extra 3dB of noise isolation beyond that which should be required for a standard cable signal level. This wont affect boxes where the signal levels are within proper internationally agreed specifications

If this is the case the problem would obviously of become worse when VM switched to qam256 due to the nature of noise on the higher density symbols (256 discrete phase/amplitude steps as opposed to the previous 64 steps).

[faflefevre]

the value of the resistor doesnt change and the resistor isnt r6 as lincsat says.
when the phoenix was first released this mod wasnt even needed as the coder stated when the qam rate started changing from 64 to 256 this is when the mod had an effect.
basically the psu mod enables the opto coupler to monitor the noise levels inside the tuner and when the noise level reaches its tolerence the opto coupler will isolate (reduce the noise level) this noise level had no effect when using a qam rate of 64 but when using 256 the tuner is more sensitive to noise level hence the reason the mod is needed.
a customer had sent a power supply board to get modded when the customer got it back he fitted it and forgot to screw it in place so decided to screw the board down while the box was powered to the mains.you can guess what happened next the screw left his screwdriver and fell into a live power supply and blew it into orbit
so his next move is to contact his supplier demanding a refund or replacement he is going down the paypal claims route is this really fair on the seller
i think not

[lincsat]

the value of the resistor doesnt change and the resistor isnt r6 as lincsat says.

On the boards that I have, the R6 resistor is different, it is 47K on the 2011 board and 10R on the 2013 board - it is definitely different on the 2 boards. Like I said, I don't know if this is the "mod" to which you refer but can confirm 100% that the values are different on the boards that I have.

If you know exactly what the "mod" is, then tell us here.

[Digicom]

Thought faflefevre has already mentioned the reason for the mod not being public?

a customer had sent a power supply board to get modded when the customer got it back he fitted it and forgot to screw it in place so decided to screw the board down while the box was powered to the mains.
you can guess what happened next the screw left his screwdriver and fell into a live power supply and blew it into orbit.
so his next move is to contact his supplier demanding a refund or replacement he is going down the paypal claims route is this really fair on the seller

If you know exactly what the "mod" is, then tell us here.

[faflefevre]

after looking at a power supply board today and from what lincsat has said about the change in value of resistors then it looks like its a different method of doing the mod but gives the same results as both are connected to the same dc supply line.
the method of changing value rather then the position of cetain resistors makes it safer as theres nothing connected to the print side of the psu (inches away from the metal chassis) plus its faster during the assembly process
so its safe to say the newer boxes have already been done

[ASEK]

well that means theres more than one secret repairer on the go, I wonder does it invalidate the warranty? or do kv admin cover this hush hush work?

[faflefevre]

i think you misunderstand..the makers will have changed the value of the resistor as a standard practice now so not really classed as a modification..
happens all the time with tvs the makers find a weakness people sell mod repair kits to make them more reliable then any new tvs made after the weakness has been identified has the changes already done at the assembly stage and no longer classed as a modification as any newer models have had this done before leaving the factory.

[ASEK]

oh I thought member lincsat had his modded and that's what came back?

[faflefevre]

read the thread mate a mains smoothing capacitor holds a charge of 330v dc so i wouldnt consider that a static shock the mains bridge rectifier has raw mains feeding it so touching that is the same as putting your fingers into a main socket.
plus people who cannot solder or use an iron with a high wattage will damage the solder print making the box useless not to mention soldering a resistor on to the print side of the pcb inches away from the metal chassis..
plus the fact that the newer boxes have already been done by the sound of it using a different method so some people wont realise this and do the mod again can you imagine the result of that
need i go on
if your paying 50p for a resistor then your getting ripped off you shouldnt be paying much more the 1p
as for a 50p resistor thats expensive more like 1p each

[faflefevre]

i think he is refering to his new stock mate but could be wrong

[ASEK]

i think he is refering to his new stock mate but could be wrong

yeah he will have to confirm I thought he said he sent his away and that was the change (mod) done on it apologies if im wrong.

[faflefevre]

just looked at another 850 power board customer has had it over 1 year and the value of r6 is 10 ohms and also spoke to someone who has the most recent 850 and the mod has been done in the usual way in the factory so sounds like its nothing to do with a change in value of r6.
i have tried this 850 before the mod ssp3 and ssp4 have a really bad patterning effect on the bottom half of the screen i have modded it and the patterning effect has gone instantly.
so basically anyone buying a new 850 will have had the mod done already anyone who has had it a while have not nothing to do with the value of the r6 resistor 47k compared to 10ohms is a massive difference.
to lincsat areyou sure you havnt looked at r1 or r2 as these are both 47k