• Hello and Welcome to HiFiVision.com - an online community for the home entertainment and tech enthusiasts!

    If you would like to ask a question, participate in a discussion and view attachments please Register yourself.

DIY Repairs - A saturday well spent!

superczar

Active Member
Joined
Feb 5, 2008
Messages
322
Points
43
One of my old Paradigm Amplifiers had gone bust some time ago when someone in the house accidentally plugged the 110V device into a regular 220V socket

On Friday, my trusted old retina MacBook started artifacting/crashing the moment it would come under any kind of CPU strain making me realise that the motherboard is probably failing
Looked up a replacement machine on amazon only to realise that new MacBooks have been launched but availability is at least a month or two away.
Not willing to live with a windows laptop in the interim, I decided to tell the home ministry that I shall be ensconsed in my study evening onwards and all other worldly chores can take a hike for a day!

Pulled out my tool box and other associated paraphernalia and glad to report that both devices are back to the world of the living! :)

Paradigm Amplifier - PW Amp with Anthem Room correction
Dual board setup with the lower board containing the microprocessor/wifi/ Preamp and the upper board with SMPS and Power Amplifier
The power Amp was a TDA8954 with a symmetrical power requirement
The lower board had a separate power section on the SMPS
The zener diodes for the respective section were 2 X 22V and 5V respectively

The 5V bit was easy but getting a 22V symmetrical (+/-22V) wasn't- Looked up the data sheet for the TDA8954 which revealed a power requirement between +/-12.5-+/- 42V
Improvised a bit by hooking up two old Dell laptop supplies to yield a ghetto +19.5 V: 0 : -19.5V supply and a separate rail for the +5V microprocessor section
Lo- behold . the device sprang back to life and works as good as ever (probably better than before considering the beefier dual 5A supplies)

IMG_3492 (1).jpg
IMG_3491 (1).jpg
On the ghetto workbench being tested (kitchen sill)

Retina Macbook

A vast majority of failures on super-compact boards is because of microscopic fractures on the solder joints

Since it isn't practically possible to spot such soldering issues , the only viable solution is a solder reflow by using a controller temperature blast on a SMD reflow unit (which are super-expensive specialised equipment).

As a workaround , I have had good success with a makeshift reflow using a heat-gun and an IR thermometer in the past with a couple off errant boards but nothing this tiny ((For context, the size of the board below is the length of a wrigleys gum-stick)
Since I had nothing to lose, I decided to use the same ploy again by unplugging all the connectors and gently heating the board till the IR thermo read 225C.

IMG_0168 (1).jpgIMG_0169 (1).jpg

After the board had cooled down, plugged everything back in again and , well, typing this out on the said retina MacBook!
All in all - and an upset home ministry aside - A saturday evening well spent :)
 
SPONSORED ADS

SPONSORED ADS

raghupb

Well-Known Member
Joined
Sep 11, 2015
Messages
1,647
Points
113
Location
Bengaluru
<snip>
All in all - and an upset home ministry aside - A saturday evening well spent :)
Do this the net time you plan something like this.
- a couple of days before (say thursday), sneak into the kitchen and disconnect a wire inside the mixer or toaster
- register a genuine complaint from HM; patiently hearing her out
- before you tinker with AV stuff, fix the sabotaged unit; earn brownie points
Cheers,
Raghu
 

anandshah

New Member
Joined
Nov 1, 2018
Messages
21
Points
3
Location
Pune
One of my old Paradigm Amplifiers had gone bust some time ago when someone in the house accidentally plugged the 110V device into a regular 220V socket

On Friday, my trusted old retina MacBook started artifacting/crashing the moment it would come under any kind of CPU strain making me realise that the motherboard is probably failing
Looked up a replacement machine on amazon only to realise that new MacBooks have been launched but availability is at least a month or two away.
Not willing to live with a windows laptop in the interim, I decided to tell the home ministry that I shall be ensconsed in my study evening onwards and all other worldly chores can take a hike for a day!

Pulled out my tool box and other associated paraphernalia and glad to report that both devices are back to the world of the living! :)

Paradigm Amplifier - PW Amp with Anthem Room correction
Dual board setup with the lower board containing the microprocessor/wifi/ Preamp and the upper board with SMPS and Power Amplifier
The power Amp was a TDA8954 with a symmetrical power requirement
The lower board had a separate power section on the SMPS
The zener diodes for the respective section were 2 X 22V and 5V respectively

The 5V bit was easy but getting a 22V symmetrical (+/-22V) wasn't- Looked up the data sheet for the TDA8954 which revealed a power requirement between +/-12.5-+/- 42V
Improvised a bit by hooking up two old Dell laptop supplies to yield a ghetto +19.5 V: 0 : -19.5V supply and a separate rail for the +5V microprocessor section
Lo- behold . the device sprang back to life and works as good as ever (probably better than before considering the beefier dual 5A supplies)

View attachment 37275
View attachment 37274
On the ghetto workbench being tested (kitchen sill)

Retina Macbook

A vast majority of failures on super-compact boards is because of microscopic fractures on the solder joints

Since it isn't practically possible to spot such soldering issues , the only viable solution is a solder reflow by using a controller temperature blast on a SMD reflow unit (which are super-expensive specialised equipment).

As a workaround , I have had good success with a makeshift reflow using a heat-gun and an IR thermometer in the past with a couple off errant boards but nothing this tiny ((For context, the size of the board below is the length of a wrigleys gum-stick)
Since I had nothing to lose, I decided to use the same ploy again by unplugging all the connectors and gently heating the board till the IR thermo read 225C.

View attachment 37276View attachment 37277

After the board had cooled down, plugged everything back in again and , well, typing this out on the said retina MacBook!
All in all - and an upset home ministry aside - A saturday evening well spent :)
Supercar Super effort , can you help i have MBP 13" retina spited coffee board not working
regards
anand shah
Pune
9867199941
 

arunkvivek

Well-Known Member
Joined
Dec 2, 2015
Messages
501
Points
63
Location
Bangalore
Do this the net time you plan something like this.
- a couple of days before (say thursday), sneak into the kitchen and disconnect a wire inside the mixer or toaster
- register a genuine complaint from HM; patiently hearing her out
- before you tinker with AV stuff, fix the sabotaged unit; earn brownie points
Cheers,
Raghu
That's a wily idea!!!
 

superczar

Active Member
Joined
Feb 5, 2008
Messages
322
Points
43
Supercar Super effort , can you help i have MBP 13" retina spited coffee board not working
regards
anand shah
Pune
9867199941
A coffee spill would have possibly caused a short - If you are lucky, it may not have killed a component but its a 50:50 thing.
Your best bet would be to pull out the board and dump it in Isopropyl alcohol for a few hours.

I can help out on a weekend if you are keen
 

anandshah

New Member
Joined
Nov 1, 2018
Messages
21
Points
3
Location
Pune
A coffee spill would have possibly caused a short - If you are lucky, it may not have killed a component but its a 50:50 thing.
Your best bet would be to pull out the board and dump it in Isopropyl alcohol for a few hours.

I can help out on a weekend if you are keen
Thanks will try boss.
 
SPONSORED ADS

Top