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 > >> >> > > >> >> > > >> > >>>************************************************************************* * > JS> ** > >> >>* > >> >> > Classifieds! Buy or Sell! > >> >> > http://sell.tech-assist.org > >> >> > The Tech Address Book: > >> >> > http://www.tech-assist.org/secure/tip/contact.htm > >> >> > Add a Repair Tip Here, or Change/Remove your Email Address: > >> >> > http://www.tech-assist.org/secure/tip/main.htm > >> >> > Lost Password: > >> >> > http://www.tech-assist.org and select "Lost your Login Info?". > >> >> > Email Archives: > >> >> > //www.freelists.org/archives/techassist/ > >> >> > > >> >> > > >> >> > >> >> > >> > >>>************************************************************************* * > JS> *** > >> >>Classifieds! Buy or Sell! > >> >>http://sell.tech-assist.org > >> >>The Tech Address Book: > >> >>http://www.tech-assist.org/secure/tip/contact.htm > >> >>Add a Repair Tip Here, or Change/Remove your Email Address: > >> >>http://www.tech-assist.org/secure/tip/main.htm > >> >>Lost Password: > >> >>http://www.tech-assist.org and select "Lost your Login Info?". > >> >>Email Archives: > >> >>//www.freelists.org/archives/techassist/ > >> > >> > >> > >> JC> Jorge Camboni, GY Electronics, Richardson, TX > >> > >> JC> > JS> **************************************************************************** > JS> * > >> JC> Classifieds! Buy or Sell! > >> JC> http://sell.tech-assist.org > >> JC> The Tech Address Book: > >> JC> http://www.tech-assist.org/secure/tip/contact.htm > >> JC> Add a Repair Tip Here, or Change/Remove your Email Address: > >> JC> http://www.tech-assist.org/secure/tip/main.htm > >> JC> Lost Password: > >> JC> http://www.tech-assist.org and select "Lost your Login Info?". > >> JC> Email Archives: > >> JC> //www.freelists.org/archives/techassist/ > >> > >> > JS> **************************************************************************** > JS> * > >> Classifieds! Buy or Sell! > >> http://sell.tech-assist.org > >> The Tech Address Book: > >> http://www.tech-assist.org/secure/tip/contact.htm > >> Add a Repair Tip Here, or Change/Remove your Email Address: > >> http://www.tech-assist.org/secure/tip/main.htm > >> Lost Password: > >> http://www.tech-assist.org and select "Lost your Login Info?". > >> Email Archives: > >> //www.freelists.org/archives/techassist/ > >> > > JS> **************************************************************************** * > JS> Classifieds! Buy or Sell! > JS> http://sell.tech-assist.org > JS> The Tech Address Book: > JS> http://www.tech-assist.org/secure/tip/contact.htm > JS> Add a Repair Tip Here, or Change/Remove your Email Address: > JS> http://www.tech-assist.org/secure/tip/main.htm > JS> Lost Password: > JS> http://www.tech-assist.org and select "Lost your Login Info?". > JS> Email Archives: > JS> //www.freelists.org/archives/techassist/ > > **************************************************************************** * > Classifieds! Buy or Sell! > http://sell.tech-assist.org > The Tech Address Book: > http://www.tech-assist.org/secure/tip/contact.htm > Add a Repair Tip Here, or Change/Remove your Email Address: > http://www.tech-assist.org/secure/tip/main.htm > Lost Password: > http://www.tech-assist.org and select "Lost your Login Info?". > Email Archives: > //www.freelists.org/archives/techassist/ ***************************************************************************** Classifieds! 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