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## Re: [Shop-talk] Help identifying a chip

 To: trevor@boicey.com, battmain@yahoo.com Re: [Shop-talk] Help identifying a chip DAVID MASSEY via Shop-talk Mon, 25 Feb 2019 13:51:06 +0000 (UTC) shop-talk@autox.team.net mharc@autox.team.net shop-talk@autox.team.net <1667483882.4759724.1551102666746.ref@mail.yahoo.com> x64; rv:65.0) Gecko/20100101 Firefox/65.0
 ```--===============1568231395855865002== boundary="----=_Part_4759723_132615334.1551102666740" ------=_Part_4759723_132615334.1551102666740 Content-Transfer-Encoding: quoted-printable All good stuff but a few points of clarification.=C2=A0 The LM in LM7805CT= will change depending on the manufacturer.=C2=A0 You can find L7805 or MC7= 805 or NCP7805 and others.=C2=A0 They will all work.=C2=A0 The CT indicates= the package, TO220 in this case.=C2=A0 You want the same package as what i= s in there now to avoid some cludge job hooking up a different style part.= =C2=A0 Also, these parts are current limited.=C2=A0 If there is a short dow= n stream the part will not fail, it will limit the current to the short unt= il the die temperature reaches 150 deg C at which point it will reduce the = output current and continue in this mode indefinitely.=C2=A0 These parts ar= e pretty bullet-proof.=C2=A0 About the only way they will fail is too much = voltage is applied.=C2=A0 As stated the input voltage can be as high as 35 = volts but if it is much higher the part will fail.=C2=A0 Typical failure mo= de is a short input to output and this will pass this high voltage on to th= e rest of the circuit and may cause other failures. I say may because it depends on what else is in the circuit.=C2=A0 If there= are voltage suppressors and current limiters (fuses) they may protect the = rest of the circuit.=C2=A0 It depends on what the designer put in there. We design and manufacture industrial products that are designed to operate = from a 24 Vdc supply.=C2=A0 It is not uncommon for users to try to power th= em off of 120 Vac because that is what the old part being replaced used.=C2= =A0 It was common enough that I designed a protection circuit that would mo= nitor the input power and only pass it on to the device if it was within th= e acceptable range.=C2=A0 So, instead of getting a room full of smoke the u= ser will find the part not working.=C2=A0 When they call in to complain we = tell them to use the right power.=C2=A0 They do so and the part works as ad= vertised.=C2=A0 Result: happy customer.=C2=A0=20 =20 Dave=20 =20 =20 -----Original Message----- From: Trevor Boicey via Shop-talk To: Battmain Cc: shop-talk@autox.team.net Sent: Mon, Feb 25, 2019 12:31 am Subject: Re: [Shop-talk] Help identifying a chip There are a lot of parts that will work there. As previously mentioned it's= a 1 amp 5 volt regulator in a TO220 case. (TO220 is the case style with th= ree pins and a heat sink tab with hole for a bolt to attach it to something= metal to keep it cool) Extremely common and extremely cheap part. Makes nice clean 5V from any inp= ut voltage from about 6V to about 35V. Three pins are just "input voltage 6= V-35V", "output voltage 5V", and ground. Digikey for that voltage and case shows the ubiquitous 7805 as well as comp= atible variations up to 5A: https://www.digikey.com/products/en/integrated-circuits-ics/pmic-voltage-re= gulators-linear/699?k=3D&pkeyword=3D7805&sv=3D0&pv1779=3D56&sf=3D0&FV=3D402= 03a%2Cffe002bb&quantity=3D&ColumnSort=3D0&page=3D1&stock=3D1&pageSize=3D25 Any part designated 7805-anything should work. It likely blew up because something else shorted, but if the shorting was t= emporary then it might just need replacing. Suggestion: Buy a few because they are much cheaper than postage will be, a= bout 50 cents each at Digikey in quantity <10. Solder in a new one and see = if it works or blows up again. If it blows up again, look for shorts around the device and fix those befor= e blowing up another one. Repeat until it's working or you lose interest. On Sat, Feb 23, 2019 at 11:01 AM Battmain via Shop-talk wrote: Could I use *any* MC7805CT as a replacement, as the first link shows diffe= rent models of that regulator? Some models of the regulator have variable o= utput as listed in the second link. I suspect the output should stay consta= nt for power, but since the amp output section has the pot on it, was wonde= ring if I should go with the adjustable output regulator or just stick with= a fixed output? Brian On Saturday, February 23, 2019, 9:37:17 AM EST, Pat Horne wrote: =20 =20 This chip is a voltage regulator, not the audio amplifier. The part number= indicates that it is a 5v fixed regulator.=C2=A0 Peace,=C2=A0Pat Pat Horne=C2=A0We support Habitat for Humanity On Feb 23, 2019, at 7:35 AM, Battmain via Shop-talk wrote: I did look up that model, however, here is an example from this site...MC7= 805CT Datasheet, PDF - Alldatasheet |=20 |=20 |=20 | | | | | |=20 | |=20 MC7805CT Datasheet, PDF - Alldatasheet alldatasheet.comMC7805CT Datasheet, MC7805CT PDF, MC7805CT Data sheet, MC78= 05CT manual, MC7805CT pdf, MC7805CT, datenblatt, Elec... | | | They list multiple models of that chip. The one I think is closest is...htt= p://pdf1.alldatasheet.com/datasheet-pdf/view/82852/FAIRCHILD/MC7805CT.html because of the variable output.=C2=A0 The amp does have level/volume pot on= it. The other datasheets in the list do not show a variable output. Brian On Saturday, February 23, 2019, 6:30:21 AM EST, Jeff Scarbrough wrote: =20 =20 How about LM7805CT? On Sat, Feb 23, 2019 at 2:16 AM Battmain via Shop-talk wrote: > > Finally got around to installing an amplified speaker I had sitting aroun= d for years.=C2=A0 It was supposed to be a simple install, but looks like I= fried something in the haste. > > I already picked up the capacitor in the picture,=C2=A0 but I think the r= egulator might be fried also based on the burn marks.Seems there are differ= ent models of that regulator.=C2=A0 The amp is in a 12v application.=C2=A0 = Anybody have any ideas as to what model regulator it is? (or what I could s= ubstitute it with? Will be getting it from that auction site. :) ) > Picture in the link...(that's the best I could get) https://i.imgur.com/F= IfJA4O.jpg > > I figure if I throw \$5 at it in parts, it wouldn't hurt to try. > > > Brian ------=_Part_4759723_132615334.1551102666740 Content-Transfer-Encoding: quoted-printable
All good stuff but a few points of clarification.&nb= sp; The LM in LM7805CT will change depending on the manufacturer.  You= can find L7805 or MC7805 or NCP7805 and others.  They will all work.&= nbsp; The CT indicates the package, TO220 in this case.  You want the = same package as what is in there now to avoid some cludge job hooking up a = different style part.  Also, these parts are current limited.  If= there is a short down stream the part will not fail, it will limit the cur= rent to the short until the die temperature reaches 150 deg C at which poin= t it will reduce the output current and continue in this mode indefinitely.=   These parts are pretty bullet-proof.  About the only way they w= ill fail is too much voltage is applied.  As stated the input voltage = can be as high as 35 volts but if it is much higher the part will fail.&nbs= p; Typical failure mode is a short input to output and this will pass this = high voltage on to the rest of the circuit and may cause other failures.

I say may because it depends on what else is in the c= ircuit.  If there are voltage suppressors and current limiters (fuses)= they may protect the rest of the circuit.  It depends on what the des= igner put in there.

We design and manufacture industrial products that ar= e designed to operate from a 24 Vdc supply.  It is not uncommon for us= ers to try to power them off of 120 Vac because that is what the old part b= eing replaced used.  It was common enough that I designed a protection= circuit that would monitor the input power and only pass it on to the devi= ce if it was within the acceptable range.  So, instead of getting a ro= om full of smoke the user will find the part not working.  When they c= all in to complain we tell them to use the right power.  They do so an= d the part works as advertised.  Result: happy customer.  =

Dave

-----= Original Message-----
From: Trevor Boicey via Shop-talk <shop-talk@autox.team.net>
To: Battmain <battmain@yahoo.com>
Cc: shop-talk@autox.team.net <shop-talk@autox.team.net>
Sent: Mon, Feb 25, 2019 12:31 am
Subject: Re: [Shop-talk] Help identifying a chip

There are a lot of parts that will work there. As previous= ly mentioned it's a 1 amp 5 volt regulator in a TO220 case. (TO220 is the c= ase style with three pins and a heat sink tab with hole for a bolt to attac= h it to something metal to keep it cool)

Extremely common and extremely cheap part. Makes nice clean 5V from an= y input voltage from about 6V to about 35V. Three pins are just "input volt= age 6V-35V", "output voltage 5V", and ground.

Digikey for that voltage and case shows the ubiquitous 7805 as well as= compatible variations up to 5A:

Any part designated 7805-anything should work.

It likely blew up because something else shorted, but if the shorting = was temporary then it might just need replacing.

Suggestion: Buy a few because they are much cheaper= than postage will be, about 50 cents each at Digikey in quantity <10. S= older in a new one and see if it works or blows up again.

If it blows up again, look for shorts around the device and fix those = before blowing up another one.

Repeat = until it's working or you lose interest.

On Sat, Feb 23, 2019 at = 11:01 AM Battmain via Shop-talk <shop-talk@autox.team.net> wrote:
=20
Could I use *any* MC7805CT as a replacement, as the first link shows d= ifferent models of that regulator? Some models of the regulator have variab= le output as listed in the second link. I suspect the output should stay co= nstant for power, but since the amp output section has the pot on it, was w= ondering if I should go with the adjustable output regulator or just stick = with a fixed output?

Brian

=20
<= td colspan=3D"1" rowspan=3D"1" class=3D"yiv4516048183gmail-m_-5809008202927= 118149ydp4db1db92yiv6690341354ydp3e0f82ebcard-richInfo2" style=3D"text-alig= n:left;padding:15px 0px 0px 15px;vertical-align:top;">

MC7805CT Datasheet, PDF - Alldatasheet

alldatasheet.com
MC7805CT Datasheet, MC7805CT PDF, MC7805= CT Data sheet, MC7805CT manual, MC7805CT pdf, MC7805CT, datenblatt, Elec...=

They list multiple models of that chip. The one I think is closest is.= ..
http://pdf1.alldat= asheet.com/datasheet-pdf/view/82852/FAIRCHILD/MC7805CT.html
because of the variable output.  The amp does have level/volume p= ot on it. The other datasheets in the list do not show a variable output.

Brian

=20
=20
=20 =20
On Saturday, February 23, 2019, 6:30:21 AM EST, Jeff Sc= arbrough <fishplate@gmail.com> wrote:
=20

=20

=20

On Sat,= Feb 23, 2019 at 2:16 AM Battmain via Shop-talk
<
shop-talk@autox.team.net&g= t; wrote:
>
> Finally got around = to installing an amplified speaker I had sitting around for years.  It= was supposed to be a simple install, but looks like I fried something in t= he haste.
>
> I already picked up= the capacitor in the picture,  but I think the regulator might be fri= ed also based on the burn marks.Seems there are different models of that re= gulator.  The amp is in a 12v application.  Anybody have any idea= s as to what model regulator it is? (or what I could substitute it with? Wi= ll be getting it from that auction site. :) )
> Pictur= e in the link...(that's the best I could get) https://i.imgur.com/FIf= JA4O.jpg
>
> I figure if I th= row \$5 at it in parts, it wouldn't hurt to try.
>
>
> Brian

------=_Part_4759723_132615334.1551102666740-- --===============1568231395855865002== Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Shop-talk@autox.team.net Archive: http://www.team.net/pipermail/shop-talk --===============1568231395855865002==-- ```
 Current Thread [Shop-talk] Help identifying a chip, Battmain via Shop-talk Re: [Shop-talk] Help identifying a chip, Jeff Scarbrough via Shop-talk Re: [Shop-talk] Help identifying a chip, Battmain via Shop-talk Re: [Shop-talk] Help identifying a chip, Battmain via Shop-talk Re: [Shop-talk] Help identifying a chip, Jeff Scarbrough via Shop-talk Re: [Shop-talk] Help identifying a chip, Pat Horne via Shop-talk Re: [Shop-talk] Help identifying a chip, John Innis via Shop-talk Re: [Shop-talk] Help identifying a chip, Trevor Boicey via Shop-talk Re: [Shop-talk] Help identifying a chip, DAVID MASSEY via Shop-talk Re: [Shop-talk] Help identifying a chip, DAVID MASSEY via Shop-talk <=