[TechAssist] Re: Philips HOT BU2508DF Mis-labeled
- From: "J Silverman" <greentron@xxxxxxx>
- To: "Intrepid Video Support" <support@xxxxxxxxxxxxxxxxxx>,<techassist@xxxxxxxxxxxxx>
- Date: Thu, 1 Apr 2004 14:19:30 -0500
I cant argue with you as I rarely make such a measurement. I am just
forwarding information that techs have posted on Nesdanet in the past
concerning this problem.
Jerry Silverman
Greentron Inc
4 Newland Ave
Greenville SC 29609
864 232 3889
Fax 271 2080
mailto:greentron@xxxxxxx
----- Original Message -----
From: "Intrepid Video Support" <support@xxxxxxxxxxxxxxxxxx>
To: "J Silverman" <greentron@xxxxxxx>; <techassist@xxxxxxxxxxxxx>
Sent: Wednesday, March 31, 2004 6:00 PM
Subject: Re: [TechAssist] Re: Philips HOT BU2508DF Mis-labeled
> Then you need a new ohm meter...
> I don't think I have ever seen a HOT with lower than 50 ohms.
>
> Jeff Dougherty
> Intrepid Video TV/VCR
> 263 S Front St
> Steelton PA 17113
> fax...717-564-4952
> www.intrepid-video.com www.tech-repair.net
>
> ----- Original Message -----
> From: "J Silverman" <greentron@xxxxxxx>
> To: "Intrepid Video Support" <support@xxxxxxxxxxxxxxxxxx>;
<techassist@xxxxxxxxxxxxx>
> Sent: Wednesday, March 31, 2004 3:59 PM
> Subject: Re: [TechAssist] Re: Philips HOT BU2508DF Mis-labeled
>
>
> I never heard of a "too low" resistance complaint. Complaint was always
that
> the resistance was too high. On some HOTs the normal level is about 25
ohms.
> Jerry Silverman
> Greentron Inc
> 4 Newland Ave
> Greenville SC 29609
> 864 232 3889
> Fax 271 2080
> mailto:greentron@xxxxxxx
> ----- Original Message -----
> From: "Intrepid Video Support" <support@xxxxxxxxxxxxxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>; <greentron@xxxxxxx>
> Sent: Wednesday, March 31, 2004 9:57 AM
> Subject: Re: [TechAssist] Re: Philips HOT BU2508DF Mis-labeled
>
>
> > If the resistance is too low, same thing.
> > Ideal resistance should be in the 60-70 ohm range.
> >
> > Jeff Dougherty
> > Intrepid Video TV/VCR
> > 263 S Front St
> > Steelton PA 17113
> > fax...717-564-4952
> > www.intrepid-video.com www.tech-repair.net
> >
> > ----- Original Message -----
> > From: <greentron@xxxxxxx>
> > To: <techassist@xxxxxxxxxxxxx>
> > Cc: "Corey Brazell" <cohbraz@xxxxxxxxxxxxxx>; <techassist@xxxxxxxxxxxxx>
> > Sent: Tuesday, March 30, 2004 10:42 PM
> > Subject: [TechAssist] Re: Philips HOT BU2508DF Mis-labeled
> >
> >
> > Those are counterfeit. Regardless of what other differences there are,
> they will burn out quickly without
> > the resistor. The resistor damps parasitic oscillations and has to be as
> close to the junction as
> > possible, which is why they are fabricated internally. No distributor
> intentionally ships counterfeits but
> > we hear about this thing all the time. Some techs keep a list of the
> resistor measurement for a given type
> > of hot and check all of the new stock against the list. If the resistor
> value is more than 20% above the
> > nominal value, they know from experience that the hot wont last.
> > J Silverman
> >
> >
> > > That's what it said on PartSeeker, but when I ordered it, it subbed to
> that
> > > BU2508DF.
> > >
> > > Regardless, any BU2508DF should have the dampening diode and biasing
> > > resistor; I have several older BU2508DF that do and read 40 ohms. But,
> > > these new ones that I ordered that all have the same date code not
have
> > > that resistor. There is around a 2 Meg Ohm resistance between Base and
> > > Emitter.
> > >
> > > So, I have two different BU2508DF transistors. Older ones that are
> correct,
> > > and newer ones that do not have the biasing resistor.
> > >
> > > Also, I just noticed that the new DF's don't look the same as the
older
> > > ones. It looks like they have been re-stamped. The front of these look
> as
> > > if they have been fine-sanded to a smooth even surface and then
stamped.
> My
> > > older DF's Have three round indentions on the front face. One in the
> middle
> > > near the bottom, and two toward the top near each side. These new ones
> are
> > > smooth all the way across. As a matter of fact, I have one that is
> stamped
> > > on both sides!
> > >
> > > Corey Brazell
> > > Audio Video Electronics
> > > 12169 SC Hwy 121
> > > Newberry SC 29108
> > >
> > >
> > > > [Original Message]
> > > > From: Intrepid Video Support <support@xxxxxxxxxxxxxxxxxx>
> > > > To: <techassist@xxxxxxxxxxxxx>
> > > > Date: 3/30/2004 3:29:48 PM
> > > > Subject: [TechAssist] Re: Philips HOT BU2508DF Mis-labeled
> > > >
> > > > Corey,
> > > > Thanks for the information, but that part number is for Philips
S2055,
> > > 610597
> > > >
> > > > Jeff Dougherty
> > > > Intrepid Video TV/VCR
> > > > 263 S Front St
> > > > Steelton PA 17113
> > > > fax...717-564-4952
> > > > www.intrepid-video.com www.tech-repair.net
> > > >
> > > > ----- Original Message -----
> > > > From: "Corey Brazell" <cohbraz@xxxxxxxxxxxxxx>
> > > > To: <techassist@xxxxxxxxxxxxx>
> > > > Sent: Tuesday, March 30, 2004 1:07 PM
> > > > Subject: [TechAssist] Philips HOT BU2508DF Mis-labeled
> > > >
> > > >
> > > > I have received two separate shipments of these BU2508DF transistors
> from
> > > > Philips, and the transistors do not have the built-in Base-Emitter
> bias
> > > > resistor. They seem to be a BU2508AF. The transistors in both
> shipments
> > > > have the same date code: 0231 C2
> > > >
> > > > Philips is now running a Stock Check on these parts. They may also
be
> > > under
> > > > part number 4835 130 47897.
> > > >
> > > > If you have any of these type HOTs, check them!
> > > >
> > > >
> > > > Corey Brazell
> > > > Audio Video Electronics
> > > > 12169 SC Hwy 121
> > > > Newberry SC 29108
> > > >
> > > >
> > > >
> > > >
> > > >
> >
>
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