What is it?

This is the place for any magazine-related discussions that don't fit in any of the column discussion boards below.
Post Reply
southmetro
Posts: 7
Joined: Mon May 20, 2002 1:01 am
Location: Georgia
Contact:

What is it?

Post by southmetro » Mon May 20, 2002 8:25 am

While repairing a VCR SMPS, I noticed a component I have never seen before. It's labeled PR1 on the board, is housed in a 3-pin SIP (MT2) package like a 2SC2021 transistor and has "N10015" stamped on it. Research showed nothing. Any ideas? Thanks.

User avatar
Chris Smith
Posts: 4325
Joined: Tue Dec 04, 2001 1:01 am
Location: Bieber Ca.

Re: What is it?

Post by Chris Smith » Mon May 20, 2002 9:59 am

The Master IC locator shows nothing. Is there a Brand Name or Logo on it?

southmetro
Posts: 7
Joined: Mon May 20, 2002 1:01 am
Location: Georgia
Contact:

Re: What is it?

Post by southmetro » Mon May 20, 2002 8:20 pm

No logo. Below the "N10015" and to the right is something that looks like this: .8_o. In reality, the dot is at the top, the loops of the eight are squared off and the o is on top of the _. Couldn't draw it right here.

User avatar
Edd
Posts: 885
Joined: Sun Jan 27, 2002 1:01 am
Location: Dallas Tx
Contact:

Re: What is it?

Post by Edd » Tue May 21, 2002 3:23 pm

It wud be helpful to have the model, yr and manuf of the VCR. Is the part a troubleshooting suspect or merely a curiosity,and U have already
buttoned up the unit? Is the part in the hot side
of the supply or past the xfmr sec in the cold derived voltages/reg section(s)?
On computer SMPS's it is very in design vogue to use TI's TL431 Precision Adjustable shunt Reference/Regulator in the secondary feedback
back loop circuitry with sampling transferred from pri to sec via an optical isolator.
Now, any chance of reading that PR1 as being
....Precision Reference 1 ??? Most TI units are shipped as the the TO-92 config but it also is offered as the PK package which wud resemble your 2SC2021 casing, except the indexing gouge on top of the case is not utilized. If there's marking on the pcb there might be 1 2 3 and in TL431 design # 2 wud be the anode and it goes to gnd.
Your symbolization ID description sure seems like KOREAN script and it could be the logo of a secondary sourcing of this item from an overseas manuf. 73's de Edd
;) ;) ;)

southmetro
Posts: 7
Joined: Mon May 20, 2002 1:01 am
Location: Georgia
Contact:

Re: What is it?

Post by southmetro » Wed May 22, 2002 7:21 am

Thanks for the effort, Edd. It's a Quasar VH6300, no schem. Looks to be way past the transf. and the opto., but still on p/s board. Could be a problem as two pins show a short. Does have notch & beveled edge like transist.

viveguy
Posts: 37
Joined: Wed Feb 06, 2002 1:01 am
Location: Grand Rapids MI
Contact:

Re: What is it?

Post by viveguy » Thu May 23, 2002 9:18 am

It is a power resistor.

southmetro
Posts: 7
Joined: Mon May 20, 2002 1:01 am
Location: Georgia
Contact:

Re: What is it?

Post by southmetro » Thu May 23, 2002 8:21 pm

Thanks, Al, but could you elaborate?

User avatar
Edd
Posts: 885
Joined: Sun Jan 27, 2002 1:01 am
Location: Dallas Tx
Contact:

Re: What is it?

Post by Edd » Fri May 24, 2002 5:11 pm

Sir Southmetro ???:
Your Quasar VH6300 info said it all . Motorola's Quasar name acquired by Matsushita in the +70's and seem
like it faded in the lo 90's. I'm no longer "blind" with this newly provided info. Matsushita family- circa 1987.
1>Scratch the TL431 possibility, however those were Japan's days of the cheaper KOREAN labor pool and
the second sourcing of your parts being manuf by them...........thus, your aptly described K script logo .
2>Scratch the suggestion of power resistor ....like.....Power Resistor 1. Notwithin the small casing config and being built on a 100 mil die!!!
3>What you last thought was xstr, but didn't U notice... wheres that missing center lead ?
4>What U have is a circuit ProtectoR 1. Mainly used back in the 80's in 2 configs; as a 2 leaded TO-92 and
in your casing......with 2 leads. Ur unit you confirmed as shorted (good) and its rating is 600 ma (FIO).
Since you supposedly haven't fixed it yet...lets go .Assuming Ur 1.6A line fuse ok (since U didn't mention it)
This wud mean a soft failure of the ps /vs/ a hard one which wud take out that fuse and the plastic to-220
sw mode pwr xstr Q1. Put Ur ear on top of the ps and plug into AC, if U hear the shriek of SMPS start up; the pri cktry and opti coupler feed back loop cktry are working ok. Move to SMPS xfmr sec and ck the 4 diodes conn to its windings that are prov the 4 cold LVDC supplys deriv fm it; I believe U will find all O.K. Xfmr
# 11 feeds thru D11 and provides ur raw +5 LVDC and ...lo...the PR 1 !!! then to filt cap C15 then thru an inductor to cap C16 ...for Ur pure 5 VDC source. Same ident procedure for Ur +14 VDC supply except diff supply diode and its filters are C12 and C13. Ur 48 VDC supp is derived from C 11 and its assoc diode.Ur -33 VDC tuner varactor supply is deriv fm C 14 and its assoc diode.
C11=10uf/50vdc C12 & 13=330uf/18vdc C14=10uf/50vdc C15 & 16=330uf/6vdc, are comp values.
Ur problem shud be part/all of the 330uf units.Years of that ringing 100khz sq pulse hammering the
"innards" of those caps has warmed them up and "steamed" up the electrolyte and as it has out
gassed thru the seal, produced an increased ESR and snowballed its degradation.Take a miniscule amt of the $50-75
labor savings in ur pocket and shotgun (replace all) the above units UNLESS U can scope test the AC on them while operating or have a cap ESR meter for analysis. Back on the hot pri side theres also C5 a 4.7ufd/200vdc elect is used in a spike/damping network off the Q1 coll thats prone to failure....prev maintenance.USE 105 deg temperature rating replacement units. Give forum feedback for forum benefit 'cause this design was carried forward> 5 yrs and second sourced as: SYLVANIA....PHILCO......PANASONIC....MAGNAVOX units also; I'll just guarantee that some forum members will have the same little leak spring out and sink their boats also.
73's de Edd ;) ;) ;) <p>[ May 24, 2002: Message edited by: Edd Whatley ]<p>[ May 24, 2002: Message edited by: Edd Whatley ]</p>

southmetro
Posts: 7
Joined: Mon May 20, 2002 1:01 am
Location: Georgia
Contact:

Re: What is it?

Post by southmetro » Sun May 26, 2002 1:34 pm

Thanks, Edd. I'm repairing this thing right now. Lightning got C5,D4,D16,IC1,Q1,Q2,R23 & the fuse. Just had never seen a PR in that case w/3 leads. Thanks, again. Do you happen to know the value of R23? Is it 68? Stuart.

User avatar
Edd
Posts: 885
Joined: Sun Jan 27, 2002 1:01 am
Location: Dallas Tx
Contact:

Re: What is it?

Post by Edd » Tue May 28, 2002 10:55 am

Stuart:
U DID have a hard failure then! Just short of a meltdown. No R23 # on my equiv Mag fiche but if D4 shorted see if it might also be MAG's R(100)5,a 82 ohm 1 w fm cathode of ur bad D(100)4 to the joined Q1 base and Q2 emitter.Theres also MAg R(100)9, a 4.7 ohm between D4's anode and T1's term 5. FIO ur C5 is shunted by a 33K 2w res. CUL 73's de Edd

viveguy
Posts: 37
Joined: Wed Feb 06, 2002 1:01 am
Location: Grand Rapids MI
Contact:

Re: What is it?

Post by viveguy » Wed May 29, 2002 6:31 am

Check the Vishay/Dale or Caddock websites.You will see power resistors offered in that package.You can catch the links through epanorama.net.

southmetro
Posts: 7
Joined: Mon May 20, 2002 1:01 am
Location: Georgia
Contact:

Re: What is it?

Post by southmetro » Sat Jun 08, 2002 7:05 am

Mystery solved! I found a Panasonic VCR that uses almost the identical SMPS. The schematic identifies PR1 as a UN10015, a three-terminal protector, one of which is unused. Many thanks to all who took the time to help. 73, Edd.

Post Reply

Who is online

Users browsing this forum: No registered users and 39 guests