HobbyKing Eco8 charger teardown/mods

[whatever]

After doing some repairs on old chargers ( icharger 208b and turnigy accucel 8150) I decided to open up a working HobbyKing eco 8 charger ( all chargers are 8s 150watt and all basically do same thing) just to see how it compares to those two.
Turns out the hobbyking is imax rc brand written on the circuit board. Hobbyking was probably cheapest version at the time, and I must say for the price ( from memory might have been $40australian dollars), I really cant believe that could make/sell them for that price. The quality is quite good. But i'll show some pics of teardown and show some similariities differences to the other chargers.

 

[whatever]

printed on board is imax rc brand ( note there is 107a capacitor added on rear of board by manufacturer)

 

[whatever]

top of the board view:
Layout is generally same as other chargers.
What I would refer to as mosfet bank ( not all mosfets though) where:
2nd from left is 5v regulator( in different position to the turnigy regulator) here are the info on each t0-220 from left to right:
irfz44n, l7805cv, irf4905, mhchxm mbr20100, irfz44n, silkron ssbr20100ct, utc 30n06L, irfz44n
At this point bit of a revelation:
the items with the numbers 20100 in them are schottkey diodes ( 100v 20amp), I has assumed in the turnigy charger all the to-220 packages were mosfets ( except the 5v regulator).......and going back to look at the turnigy I see two nfa14 labelled to-220 items, which no datasheet available, I assumed they were mosfets, I now think they are schottkey diodes as the hobbyking has 2 shottkeys).

note: screen has been removed fortunately it has nice connector to take it off

 

[whatever]

next pic is just high res version of the board in case anyone needs to identify components

 

[whatever]

I will have to go back and check my icharger and turnigy pictures, I've just realised I've been misunderstanding some of the t0-220 layout.
Icharger: 6 mosfets on bottom of board ( case is heatsink)
turnigy: 1 lot 5v regulator, 2xshcottkey diodes, 5 mosfets ( metal bar locks into place)
hobbyking: same as turnigy but order not same ( metal bar locks into place)
I had assumed that turnigy had 7 mosfets and one 5v regulator all t0-220 on heatsink, this was my mistake I've just realised, two of the components are named nfa14 ( cant find data on them), but looking at the hobbyking I now think they are schottkey diodes! not mosfets since the hobbyking has 2 schottkeys on the t0-220 section.

So in retrospect I can say I was extremely lucky I didn't replace all the turnigy t0-220 with mosfets ( as I did with the icharger), I only replaced one mosfet that was obviously damaged.......a stroke of luck there.
....still learning.........
Also if the icharger works on similar principle to these other chargers, there might be two schottkey diodes on the icharger board but not in t0-220 packages.
Will post more info later as I progress

 

[amberwolf]

Some relatively useless speculation: it could be an actual imax-built charger to HK's specs, or it could be HK bought some "overstock" PCBs and populated them with the cheapest parts that would "function" well enough for the price point.

 

[whatever]

useless speculation indeed