Hardware Information


Flyback Transformer-How to Locate the ABL Line


Whenever there is a complaint about monitor contrast problem I will check on the flyback transformer ABL (automatic blanking limiter) circuit. Sometimes a weak picture tube might caused contrast problem. If the picture tube is good, I will go straight to the contrast circuit. The question is how do we find where the contrast circuit located? Simple, if you have a datasheet for the video pre- amplifier ic, definitely you can find the contrast pin. For LM1203N video pre-amp ic the contrast pin is located at pin 12. Replace this ic or trace from this circuit to find the cause of the contrast problem.

From experienced, usually capacitors shorted and resistor turned into high ohms were the caused of the problem. A video pre-amplifier can also be defective. To confirm whether is circuit or ic problem, just solder out the contrast pin and switch on the monitor. If the monitor display normal picture (contrast ok) then suspect the abl line circuit. If it remain the same (dim contrast) replace the video pre-amp will usually solve the problem.

The contrast signal came from one of the pin (leg) of a flyback transformer which we called it as abl pin. Many technicians have the difficulty to trace the abl pin because usually a flyback transformer consist of around 10 pins. Some pins are B+, GROUND, AFC, ABL, X-RAY PROTECT, VCC, to HOT, HEATER, horizontal centering and etc. But there is one and simple way that i'm gone to show you how to locate the abl pin. Use two analog multimeters set to x10kohm range. Connect it in series (+ probe to - probe) and measure the flyback transformer from anode (the red cap) to all of the pins under the flyback. You have to desolder all the pin or just remove the flyback from the mainboard in order to get an accurate reading.

If either one of the pin shows a diode reading that is the abl pin. The reason we use two multimeters is because the flyback circuit internally have couple of high voltage diodes connected in series. If you have a schematic diagram or any monitor or television troubleshooting book, you will see that the internal flyback diode are connected in series. By connecting two meters the ouput from the probe is around 24 VOLTS which is enough power to check the flyback internal diodes. After you have determined the abl pin, you can proceed to follow the line and find the bad components that cause the contrast problem.

Television or tv flyback transformer generally have the same design compare to monitor flyback. Whether it is a montblanc flyback transformer, rca, mitsubishi or sony flyback the checking usually is the same.

Jestine Yong is a electronic repairer and a writer. For more electronic repair information please visit his website at http://www.noahtec.com/electronic-repair-articles.htm


MORE RESOURCES:
This RSS feed URL is deprecated, please update. New URLs can be found in the footers at https://news.google.com/news


Nextgov

Navy Opens Bids on Major IT Hardware Contract That Includes As-A-Service Options
Nextgov
The End User Hardware solicitation, or EUHW, covers most end-user devices, such as laptops, desktops, tablets, 2-in-1 detachable devices, ultra-small desktops, thin or zero client devices and ruggedized devices. The performance work statement notes the ...



Hardware, accessories pace 26% jump in videogame sales
Seeking Alpha
August videogame sales were again the beneficiary of healthy spending on hardware and accessories, though software rebounded to contribute for the month as well. Overall sales rose 26% for the month, to $796M, according to NPD Group. Software sales ...



9to5Google

Huawei Y9 review: Quality hardware and exceptional battery life [Video]
9to5Google
The Huawei Y9 is one of a number of devices from the Chinese brand that is aimed directly at the more affordable end of the market. There are definitely some compromises that help this phone get into wallet-friendly territory, but overall it's a pretty ...



Infosecurity Magazine

Hardware Security Revisited
Infosecurity Magazine
As Spectre and Meltdown demonstrated earlier this year, hardware is no less vulnerable to attack than any other system because hardware is an often overlooked piece of the security puzzle. Security and business professionals can habitually fail to see ...



TechCrunch

Apple Watch and other hardware reportedly spared by new Trump tariffs
TechCrunch
The latest round of Trump administration tariffs is set to affect a number of different industries. At least one category previously expected to be impacted, however, is likely to be spared, according to a new report from Bloomberg. According to ...
US Tariffs Now Include Wireless Routers, China RespondsTom's Hardware

all 7,745 news articles »


KGUN

Marana hardware store to reopen after being damaged by microburst
KGUN
TUCSON, Ariz. - After being closed for more than a month the ACE Hardware near Ina and Thornydale will reopen. The store was closed for repairs after sustaining roof damage during a microburst back in August. The Michaels' next door was also closed.



VentureBeat

Cisco launches Cisco Webex Edge and new videoconferencing hardware
VentureBeat
In the nearly 10 years since Cisco snatched up on-demand online meeting platform Webex, the San Jose company has become a veritable juggernaut in the videoconferencing space. More than 300 million customers tap its eponymous Cisco Collaboration ...

and more »


WVVA TV

Old hardware store in WSS set to breathe new life into town with business opportunities
WVVA TV
(White Sulphur Springs) The old Bowling Hardware store in White Sulphur Springs is about to undergo a major renovation. Developer and project manager Dave Bostic says the building will be developed into shops, a bar-b-que restaurant and a ...



ZDNet

Amazon reportedly plans to roll out more Alexa-enabled hardware
ZDNet
This device is unable to play the requested video. Amazon's voice-activated assistant Alexa has a significant presence in consumers' homes, thanks to the robust ecosystem of developers and manufacturers who are incorporating Alexa into their devices ...
Amazon is letting developers make their own Alexa GadgetsThe Verge
Amazon plans to release at least 8 new Alexa-powered devices, including a microwave, an amplifier, and an in-car ...CNBC
Amazon - Investor Relations - Press Release - Investor Relations SolutionsAmazon - Investor Relations - Press Release
Global Market Insights -Bloomberg
all 194 news articles »


FedScoop

Navy launches hardware portion of $3.5B NGEN recompete contract
FedScoop
The Space and Naval Warfare Systems Command (SPAWAR) issued a request for proposals for end-user hardware — one of two contracts under the Next Generation Enterprise Networks Recompete (NGEN-R), which is the follow-on to the five-year, $3.5 ...
Navy publishes RFP for NGEN-R hardware contractInside Defense

all 7 news articles »

Google News

home | site map
© 2007