RC India
Welcome Guest, please login or register.
 
Pages: 1 [2]  All   Go Down
0 Members and 1 Guest are viewing this topic. Topic Tools Topic Tools 
Read
« Reply #25 on: September 28, 2012, 07:14:02 PM »
lastRites
Lover of all RC
Plane Lover
Forum Hero

*****

Reputation Power: 10 
lastRites has no influence.
Offline Offline

City: Kolkata
State: West Bengal
RC Skills: Beginner
Posts: 753
Join Date: Nov, 2011



Is the problem solved? Tongue
Logged

It is the pervading law of all things organic and inorganic,
Of all things physical and metaphysical,
Of all things human and all things super-human,
Of all true manifestations of the head,
Of the heart, of the soul,
That the life is recognizable in its expression,
That form ever follows function. This is the law.
 

Read
« Reply #26 on: September 28, 2012, 07:16:00 PM »
rastsaurabh
Plane Lover
Forum Hero

*****

Reputation Power: 19 
rastsaurabh has no influence.
Offline Offline

City: Noida
State: Haryana
RC Skills: Intermediate
Posts: 1558
Join Date: Mar, 2012



NO .... i am yet to fly again but afraid that i will break my plane... any way trying to get heat sink for regulator so that heat dissipates.... what to do for the SMD 78L05 Huh??
Logged
 

Read
« Reply #27 on: September 28, 2012, 07:43:43 PM »
KALYANPRODHAN
Global Moderator
Forum Hero

*****

Reputation Power: 17 
KALYANPRODHAN has no influence.
Offline Offline

City: Kolkata
State: West Bengal
RC Skills: Intermediate
Posts: 1584
Join Date: Jul, 2010

Information sharing improves knowledge of both.



If space provide, replace with regular large 7805 with heatsink i. e. TO220 package.
Costs is Rs. 5/- at Kolkata.
Logged

We have to unite and to prove ourself to make indigenous products as well as marketing / Canvasing them. I'm sure we must achieve success if we try unitedly.
 

Read
« Reply #28 on: September 28, 2012, 07:49:28 PM »
rastsaurabh
Plane Lover
Forum Hero

*****

Reputation Power: 19 
rastsaurabh has no influence.
Offline Offline

City: Noida
State: Haryana
RC Skills: Intermediate
Posts: 1558
Join Date: Mar, 2012



Thanks Kalyan & lastrites for all the support....
Cost of IC is not of much matter...... Point is investing time..... rather than flying i am stuck in this !!!!

Will do as suggested for a to220 package 7805.

But Still i wonder the heat .. I have used 7805, 09, 12 ICs at lot many applications but they were not so hot??
Logged
 

Read
« Reply #29 on: September 28, 2012, 07:59:40 PM »
girishsarwal
Plane Lover
Forum Hero

*****

Reputation Power: 17 
girishsarwal has no influence.
Offline Offline

City: Gurgaon
State: Haryana
RC Skills: Beginner
Posts: 1420
Join Date: May, 2012

DIYer



http://www.electro-tech-online.com/general-electronics-chat/18861-heat-sink-7805-a.html
http://www.dutchforce.com/~eforum/index.php?s=e10e05c80419782fedb0c7f8a9209ec1&showtopic=21384
http://www.electronicspoint.com/l7805cv-too-hot-t23923.html

Reduce the input voltage, you'll be a happy man! You need a heatsink badly if you're dissipating over 1.5w

Your 7805 might be oscillating crazy, what caps do you have connected?

lastRites, your point makes sense that if it wasn't there earlier, why now? rastsaurabh, did you ever check the heat before replacing these, they might have been overheating all the time.

In the end, there are only two choices, either generate lesser heat or get rid of the extra generated.
Logged

gs
 

Read
« Reply #30 on: September 29, 2012, 02:36:56 AM »
KALYANPRODHAN
Global Moderator
Forum Hero

*****

Reputation Power: 17 
KALYANPRODHAN has no influence.
Offline Offline

City: Kolkata
State: West Bengal
RC Skills: Intermediate
Posts: 1584
Join Date: Jul, 2010

Information sharing improves knowledge of both.



The excess heat in RF Amplifier transistor may be so hot so as to burn the transistor instantly if not antenna properly matched and reflected wave generated. But the regulator have no such issue except loading current and potertial difference between input and output voltage.

However, I am waiting for some study materials for clearing some issue simply. God knows how long I have to wait. Grin
Logged

We have to unite and to prove ourself to make indigenous products as well as marketing / Canvasing them. I'm sure we must achieve success if we try unitedly.
 

Read
« Reply #31 on: September 29, 2012, 03:06:25 AM »
abhay
Plane Lover
Forum Hero

*****

Reputation Power: 11 
abhay has no influence.
Offline Offline

City: Lucknow
State: Uttar Pradesh
RC Skills: Beginner
Posts: 886
Join Date: Nov, 2010

Wrong Brothers



Kalyan Da, would not the circuitry get effected if he replaces 78L05 with regular one, in case there is some faulty bridging after the output. Huh?
The actual cause of heat generation has not been found yet.
I think this(any bridging) can also be a reason for excess heat generation. Undecided
the provided IC provides 500ma of current, while the regular is designed for many times more(2a i guess,dont know exactly).
So there are chances of frying the post circuitry i guess.
Logged

I can take off and fly well. Its landing which sucks Bang HeadBang Head
 

Read
« Reply #32 on: September 29, 2012, 07:09:24 AM »
lastRites
Lover of all RC
Plane Lover
Forum Hero

*****

Reputation Power: 10 
lastRites has no influence.
Offline Offline

City: Kolkata
State: West Bengal
RC Skills: Beginner
Posts: 753
Join Date: Nov, 2011



 I agree
Logged

It is the pervading law of all things organic and inorganic,
Of all things physical and metaphysical,
Of all things human and all things super-human,
Of all true manifestations of the head,
Of the heart, of the soul,
That the life is recognizable in its expression,
That form ever follows function. This is the law.
 

Read
« Reply #33 on: September 29, 2012, 11:01:15 AM »
KALYANPRODHAN
Global Moderator
Forum Hero

*****

Reputation Power: 17 
KALYANPRODHAN has no influence.
Offline Offline

City: Kolkata
State: West Bengal
RC Skills: Intermediate
Posts: 1584
Join Date: Jul, 2010

Information sharing improves knowledge of both.



As this regulator feeds power to entire ckt, it should be hot. And it was earlier soldered with PCB foil as heatsink. Moreover, Now signal stable means, some leaky capacitor replacement improves some load behavior.
And,
troubeshooting needs step-by-step approach.
Logged

We have to unite and to prove ourself to make indigenous products as well as marketing / Canvasing them. I'm sure we must achieve success if we try unitedly.
 

Read
« Reply #34 on: September 30, 2012, 12:20:42 AM »
rastsaurabh
Plane Lover
Forum Hero

*****

Reputation Power: 19 
rastsaurabh has no influence.
Offline Offline

City: Noida
State: Haryana
RC Skills: Intermediate
Posts: 1558
Join Date: Mar, 2012



The TX is new and rarely used ...... why i suspected TX was that the model plane flew well initially but all of a sudden became uncontrolable and crashed. When i could not find any reason, I opened the TX and felt the 7805 to be hot so there is no pre post study. I used new alkaline batteries with were 12Volts but now are used up to 11Volts so i can expect some improvement when i fly.

@ girish - the cap i used are 47Mfd 25Volt Philips make. Replaced all 6 of them all were same value old ones are some unknown company.
Logged
 

Read
« Reply #35 on: September 30, 2012, 08:58:36 AM »
KALYANPRODHAN
Global Moderator
Forum Hero

*****

Reputation Power: 17 
KALYANPRODHAN has no influence.
Offline Offline

City: Kolkata
State: West Bengal
RC Skills: Intermediate
Posts: 1584
Join Date: Jul, 2010

Information sharing improves knowledge of both.



Now insted of plane, use BEC and servos and test for at least 15 minutes at a long distance.
your tx should be stable now. All the txs are designed and optimized for NiMH and NiCD battery. So when new alkaline/dry cell is used (EMF=1.56volt), heat generation become so hot, it malfunctions. E-Sky are better in this case as they use 4 cell insted of 8 cell.

However, if final stage RF power is to be maximized, it's supply voltage should be as high as possible in addition of highly selective matched antenna using some network (PI or ladder). So a good regulator with high voltage battery (of-course within designed limit) can give higher range if not any other section malfunction. But if entire RF stage use 5 volt, then it is better to supply reduced voltage. in this case you can try to use a dummy cell (shorted one) and can get good result. If entire section works on 5 volt, you can save even 2 cell. But always test range while doing this experiment.

Good Luck.
Logged

We have to unite and to prove ourself to make indigenous products as well as marketing / Canvasing them. I'm sure we must achieve success if we try unitedly.
 

Read
« Reply #36 on: September 30, 2012, 09:45:30 AM »
lastRites
Lover of all RC
Plane Lover
Forum Hero

*****

Reputation Power: 10 
lastRites has no influence.
Offline Offline

City: Kolkata
State: West Bengal
RC Skills: Beginner
Posts: 753
Join Date: Nov, 2011



If I want to use a normal lipo to power my tx(at full charge gives 12.6v) should we use an external step down regulator? What should be stepped down voltage, 10v?
Logged

It is the pervading law of all things organic and inorganic,
Of all things physical and metaphysical,
Of all things human and all things super-human,
Of all true manifestations of the head,
Of the heart, of the soul,
That the life is recognizable in its expression,
That form ever follows function. This is the law.
 

Read
« Reply #37 on: September 30, 2012, 10:20:50 AM »
KALYANPRODHAN
Global Moderator
Forum Hero

*****

Reputation Power: 17 
KALYANPRODHAN has no influence.
Offline Offline

City: Kolkata
State: West Bengal
RC Skills: Intermediate
Posts: 1584
Join Date: Jul, 2010

Information sharing improves knowledge of both.



LiFePO are better than LiPO.
In LiPO Use 2 nos 1N4007 in series to drop out voltage.
« Last Edit: October 04, 2012, 07:38:15 PM by KALYANPRODHAN » Logged

We have to unite and to prove ourself to make indigenous products as well as marketing / Canvasing them. I'm sure we must achieve success if we try unitedly.
 

Read
« Reply #38 on: March 17, 2013, 12:17:48 AM »
streetjerk
Heli Lover
Active Member
**

Reputation Power: 2 
streetjerk has no influence.
Offline Offline

City: Kolkata
State: West Bengal
RC Skills: Beginner
Posts: 87
Join Date: May, 2012



approximately causing a drop of 1.4 Volts ??
« Last Edit: March 17, 2013, 12:25:46 AM by anwar » Logged
 

Pages: 1 [2]  All   Go Up
Jump to:  

Related Topics
Subject Started by Replies Views Last post
Gryphon GVR-7020B Voltage Regulator
Servos, Gyros and All Electronics
deepikarun 9 8538 Last post November 04, 2010, 10:13:50 PM
by deepikarun
HK radio heating issue
Radios and Receivers
rajathv8 0 2439 Last post December 06, 2010, 01:15:19 PM
by rajathv8
Range Issue with Flysky 2.4 TX 9X
Radios and Receivers
Mjet 8 4086 Last post March 23, 2013, 09:14:31 PM
by paladugu_sujith
Wanted Li-Po Voltage Regulator
Wanted
satz flying 6 2544 Last post August 28, 2014, 11:29:11 PM
by satz flying
Flysky i6 stick issue
Radios and Receivers
Drone538 2 2304 Last post May 28, 2022, 06:23:15 PM
by ANAND BARVE16