[x] Welcome at THunting.com!

A fun place to talk about Metal Detecting, Treasure Hunting & Prospecting. Here you can share finds and experience with thousands of members from all over the world

Join us and Register Now - Its FREE & EASY

THunting.com
Treasure Hunting & Metal Detecting Community
   
Advanced Search
*
Welcome, Guest! Please login or register HERE - It is FREE and easy.
Only registered users can post and view images on our message boards.
Did you miss your activation email?

Login with email, password and session length
Or Login Using Social Network Account
2
News:
Pages: 1    Go Down
Print
Share this topic on FacebookShare this topic on Del.icio.usShare this topic on DiggShare this topic on RedditShare this topic on Twitter
Tags:
0 Members and 1 Guest are viewing this topic.
Offline frannyTopic starter
Pull Tab
*

Join Date: Feb, 2009
Thank you0

Activity
0%
Posts: 13
Referrals: 0

85.00 Gold
View Inventory

Awards
« on: March 10, 2011, 09:47:42 am »
Go Up Go Down

Does anybody have the F1270 schematics? Urgently needed to fix +10V short circuit to ground. Help me, please!
Thank you,
f.


Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,21962.msg152359.html#msg152359




Logged
Offline GoldDigger1950
The Old Man and the Soil
Global Moderator
Platin Member
*****

Just call me GD.
The Old Man and the Soil
Join Date: Jun, 2009
Thank you225

Activity
0%
Male
United States
Posts: 11219
Referrals: 12

47848.00 Gold
View Inventory

Awards

Garrett Groundhog ADS, Garrett Sea Hunter, Bounty Hunter Tracker IV, Bounty Hunter Pioneer 505,Minelab Eldorado Mk II, Tesoro Compadre, Tesoro Tiger Shark & A Few Home Brew Detectors
« Reply #1 on: March 11, 2011, 04:31:19 pm »
Go Up Go Down

The most likely cause of a short in a circuit powered by battery is a capacitor, which is used to filter noise in the low voltage circuits. You can often find the culprit by visual examination. A schematic is helpful but my experience in repair has shown that in almost every case a capacitor has physical damage that you can see with the naked eye.

Attached is a photo showing you what to look for. Electrolytic capacitors fail regularly due to age, heat, over-voltage and dialectric failure. Look for swelling, cracking, peeling of the plastic and erosion of the solder on the bottom of the board. The electrolytic capacitor looks like a tiny battery shaped device made with a case of aluminum covered with plastic. Their failure is very often visible in a deformity as shown in the picture. Note the corrosion, which is actually leakage of the dialectric, the swelling of the normally flat top and any bulges in the sides of the capacitor. All of those indicate a failure. Hopefully, you can read the value and find a replacement. If not, come back and ask for recommendations for replacement values. Power circuits most often use 16uf to 1000uf capacitors rated at 25v.

The second most likely cause is the regulator in the circuit. They are most often a three legged device with a heat sink at the top. You will have to de-solder the device to test it which can sometimes damage it so be careful if you do this. I normally de-solder the output leg of the device and read the resistance of the power circuit afterward. Your device may have a part number of LM7809 or LM7810 on it although I can tell you that I have never seen a 10 volt regulator.

Third, my experience in repair also tells me that Fisher has almost always included two diodes in series with the batteries to avoid reverse installation damage. When shorted, they have absolutely no effect on the circuit unless you install a battery reversed.

Good luck and come back later to tell us how your machine is after you looked it over.

Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,21962.msg152743.html#msg152743



There are 1 attachment(s) in this post which you can not view or download

Please register for viewing them.

SwelledCapacitors.jpg


« Last Edit: March 11, 2011, 04:37:44 pm by GoldDigger1950 »
Logged

It's all about that moment when metal that hasn't seen the light of day for generations frees itself from the soil and presents itself to me.
Let's Talk Treasure!

Offline frannyTopic starter
Pull Tab
*

Join Date: Feb, 2009
Thank you0

Activity
0%
Posts: 13
Referrals: 0

85.00 Gold
View Inventory

Awards
« Reply #2 on: March 13, 2011, 12:18:00 pm »
Go Up Go Down

Many thanks for your advice.
F1270 stabiliser consists of LP2951, all ellyts except one are of tantalum type and it is difficult to see any visual changes on SMD ceramic capacitors. Short circuit has in fact 2.2 ohm resistance and I still hesitate to try to burn it out with help of a high current PC power source (for instance 3.3V/20A), as printed wires could be damaged as well. Probably small but hard current could heat the faulty component in a way that it could be identified.

Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,21962.msg153013.html#msg153013




Logged
Offline Homefire
Global Moderator
Platin Member
*****

Join Date: Jan, 2009
Thank you662

Activity
0%
Male
United States
Posts: 15906
Referrals: 0

52360.00 Gold
View Inventory

Awards
« Reply #3 on: March 13, 2011, 01:06:39 pm »
Go Up Go Down

Get your self some Freeze it. 

Cool off the suspected components and you will see what heats up first.

Regular Canned air works if you get the Liquid to come out by hold the nozzle down a bit.

You are not allowed to view links.
Please Register or Login

http://www.google.com/products/catalog?rlz=1T4GGLL_enUS357US357&q=Freeze+it+spray&um=1&ie=UTF-8&cid=3461833887564262424&sa=X&ei=-hN9TYKPM4X5rAHO0cHDBQ&ved=0CEYQ8gIwAw#


Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,21962.msg153027.html#msg153027




Logged
Offline frannyTopic starter
Pull Tab
*

Join Date: Feb, 2009
Thank you0

Activity
0%
Posts: 13
Referrals: 0

85.00 Gold
View Inventory

Awards
« Reply #4 on: March 15, 2011, 12:56:12 pm »
Go Up Go Down

I thing I?ve got it already! Previous poorly qualified owner tried to enhance the audio output and destroyed the speaker driver transistor, which took with him analog gate 4053. After removing IO short connection dissapeared! Would Fisher give me a job?

Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,21962.msg153745.html#msg153745




Logged
Offline GoldDigger1950
The Old Man and the Soil
Global Moderator
Platin Member
*****

Just call me GD.
The Old Man and the Soil
Join Date: Jun, 2009
Thank you225

Activity
0%
Male
United States
Posts: 11219
Referrals: 12

47848.00 Gold
View Inventory

Awards

Garrett Groundhog ADS, Garrett Sea Hunter, Bounty Hunter Tracker IV, Bounty Hunter Pioneer 505,Minelab Eldorado Mk II, Tesoro Compadre, Tesoro Tiger Shark & A Few Home Brew Detectors
« Reply #5 on: March 18, 2011, 08:07:33 am »
Go Up Go Down

Quote:Posted by franny
I thing I?ve got it already! Previous poorly qualified owner tried to enhance the audio output and destroyed the speaker driver transistor, which took with him analog gate 4053. After removing IO short connection dissapeared! Would Fisher give me a job?

Perhaps you should get it running before you submit a CV.

Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,21962.msg154733.html#msg154733




Logged

It's all about that moment when metal that hasn't seen the light of day for generations frees itself from the soil and presents itself to me.
Let's Talk Treasure!

Offline frannyTopic starter
Pull Tab
*

Join Date: Feb, 2009
Thank you0

Activity
0%
Posts: 13
Referrals: 0

85.00 Gold
View Inventory

Awards
« Reply #6 on: March 19, 2011, 03:16:49 pm »
Go Up Go Down

Agree, but what I need now is to collect all that switches, potentiometers, connectors, case, coil, etc., because I have received the F1270 PCB free of all that stuff.

Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,21962.msg155132.html#msg155132




Logged
Offline riden555
Foil
*

Join Date: Apr, 2012
Thank you0

Activity
0%

Russian Federation
Posts: 1
Referrals: 0

5.00 Gold
View Inventory

Awards
« Reply #7 on: April 22, 2012, 02:41:09 pm »
Go Up Go Down

Hi
Who ever can make photos pcb 1270 on both sides? I need to restore the switches on the pcb and the position of the potentiometers.
Thank you.

Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,21962.msg221000.html#msg221000




Logged
Print
Pages: 1    Go Up
Jump to:  

Powered by SMF 1.1.19 | SMF © 2005, Simple Machines | Sitemap
Copyright THunting.com