[TechAssist] Re: HOT subs in general question

  • From: "J Silverman" <greentron@xxxxxxxxxxxxxxxx>
  • To: <techassist@xxxxxxxxxxxxx>
  • Date: Thu, 31 Jul 2003 16:29:04 -0400

Its not critical if everything is working right. If something goes wrong, a
higher wattage unit might survive where a lower wattage unit will not. I
have a Diehl MK V Scanner (universal Hot sub) supposed to be almost
bulletproof. It has two TO3 HOTs in parallel. If there is B+ and you cant
find what is wrong you hook this up in place of the HOT and watch for where
the smoke comes from.
Jerry Silverman
Greentron Inc
4 Newland Ave
Greenville SC 29609
864 232 3889
Fax 271 2080
mailto:greentron@xxxxxxx
----- Original Message -----
From: "Bil Green" <tv.vcrrepair@xxxxxxxxxxx>
To: "J Silverman" <techassist@xxxxxxxxxxxxx>
Sent: Thursday, July 31, 2003 4:01 PM
Subject: [TechAssist] Re: HOT subs in general question


> I mentioned that the HOT wattage rating is not critical. An engineer from
> ECG told me that years ago, and it works for me. I have subbed HOTs
> that were rated at 150W with a 50W and there were no problems.
>
> --
> Best regards,
>
>  Bil Green
>  2001 TV VCR
>  Mammoth Lakes, CA 93546
>  760-934-2001                           mailto:tv.vcrrepair@xxxxxxxxxxx
>
> Thursday, July 31, 2003, 11:17:15 AM, you wrote:
>
> JS> The wattage rating is for the power dissipated during the turn-on and
> JS> turn-off switching. That power dissipation is much higher than the
rating
> JS> because it is averaged over the whole cycle for heating purposes.
There is
> JS> hardly any power dissipated during the on or off periods. If the
transistor
> JS> is getting hot either there is not enough drive to get it on quickly
or
> JS> there is not enough drive to shut it off quickly. There is also a
problem if
> JS> there is too much drive. Too much turn on current can heat or damage
the b/e
> JS> junction and too much turn off voltage can break down the b/e
junction. If
> JS> it runs cool you know you are OK for operation. Wheather it survives
> JS> startup, shutdown, or the failure of something else is another matter.
> JS> Jerry Silverman
> JS> Greentron Inc
> JS> 4 Newland Ave
> JS> Greenville SC 29609
> JS> 864 232 3889
> JS> Fax 271 2080
> JS> mailto:greentron@xxxxxxx
> JS> ----- Original Message -----
> JS> From: "Bil Green" <tv.vcrrepair@xxxxxxxxxxx>
> JS> To: "Jorge Camboni" <techassist@xxxxxxxxxxxxx>
> JS> Sent: Thursday, July 31, 2003 3:04 AM
> JS> Subject: [TechAssist] Re: HOT subs in general question
>
>
> >> The BUH717 is rated at 1700V. The 1500V HOTs may not last long.
> >> Hard to believe that Sony recommends a HOT replacement which
> >> does not have a damper diode (when the original one does).
> >>
> >> I recommend the D1884 through D1887 (no damper diodes) and
> >> D1878 through D1881 (have damper diodes) for most HOT subbing.
> >> You also need to have a Japanese transistor manual so you can
> >> look things up. If you buy these as original Sanyo, Toshiba,
> >> etc. you will find that they work for almost any HOT in
> >> direct view and PTVs.
> >>
> >> Saves lots of money and you rarely have to special order a
> >> HOT. Using a sub which has the same amp rating as the original
> >> is the key. More voltage and faster switching speeds is OK.
> >> Lower wattage rating is OK also. HOTs are off most of the time
> >> (~12us on, ~55us off).
> >>
> >>
> >> --
> >> Best regards,
> >>
> >>  Bil Green
> >>  2001 TV VCR
> >>  Mammoth Lakes, CA 93546
> >>  760-934-2001                           mailto:tv.vcrrepair@xxxxxxxxxxx
> >>
> >> Wednesday, July 30, 2003, 7:07:23 PM, you wrote:
> >>
> >> JC> Hi Tony. You're using a 1881 subbing a BUH517
> >> JC> but the BUH517  HAS NO DAMPER. neither the C5148,
> >> JC> so you're adding another damper to the circuit   (and it works!!)
> >> JC> which is not the best way, i believe, In those cases you should
> >> JC> use D1885/86/87. Strangely enough, Sony reccomends subbing
> >> JC> d1941 (damperless) for c4927 (damper included)
> >> JC> I had not noticed any difference between 1879 and 1881 if the 79
> >> JC> stands the current. (it will in most cases). According to Sanyo,
there
> >> JC> is no difference between 78/79/80/81 excepting the current rates
> >> JC> and the power handling. FT (gain/bandwith product) is the same,
> >> JC> so dc beta is.
> >>
> >> JC> Jorge
> >>
> >> JC> At 07:14 p.m. 30/07/03 -0500, you wrote:
> >> >>Hey Phil I have been using the D1880 and 1881 for many subs, They do
> JS> seem to
> >> >>keep the temp down and last longer. must haves in my book BUH517,
C4927,
> >> >>C5148 ( I dont like using subs on sony to many bad memorys.)
> >> >>
> >> >>Tony Saracco
> >> >>TCS ELECTRONICS
> >> >>Elgin , IL 60120
> >> >>847-695-1928
> >> >>tcselectronics@xxxxxxxxxxxxxxxx
> >> >>----- Original Message -----
> >> >>From: "Philip Bader" <tjanphyl@xxxxxxxxxxxxxxx>
> >> >>To: <techassist@xxxxxxxxxxxxx>
> >> >>Sent: Wednesday, July 30, 2003 12:30 PM
> >> >>Subject: [TechAssist] HOT subs in general question
> >> >>
> >> >>
> >> >> > A  tech friend says if he cannot get, or ID an HOT he will sub a
> >> >> > 2SD1881. Says thiis 1881 seems to be a general heavy transistor
for
> JS> at
> >> >> > least test/estimate purposes.
> >> >> > Yesterday he had a Sharp with bad HOT 2SD2586.No subs avail. OEM a
> JS> week
> >> >> > away.
> >> >> > Used an 1881 and ran cool.
> >> >> > I want to improve my TV HOT selection bin. Is there a certain
> JS> selection
> >> >> > that are "must haves"?
> >> >> > Phil Bader
> >> >> > --
> >> >> > Philip Bader
> >> >> > Jan Phyl TV Inc. (estab. 1976)
> >> >> > 3420 Recker Hwy. Winter Haven, Fl. 33880
> >> >> > Fax (863) 299-8821
> >> >> > email: tjanphyl@xxxxxxxxxxxxxxx
> >> >> >
> >> >> >
> >>
>
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> >>
> >>
> >> JC> Jorge Camboni, GY Electronics, Richardson, TX
> >>
> >> JC>
> JS>
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