Re: HP 141T Power Supply Help Needed
¿ªÔÆÌåÓýBill, ? The 141T that I purchased from Valuetronics now has a new fan and the power transistor sockets have been replaced. Now the 1A fuses on the 8552 IF module are popping.? I built a fixture that I can monitor the basic supply voltages with out the plugins in and the 141T covers on.? ?It turns out that there is an over voltage crowbar circuit in the IF module that fires at -15V.? I took some startup scope traces and they show that the -12.6V over shoots to -15.2V and the +100 overshoots as well.? Since these are tracking regulators and the basic reference is the neon tube in the +100V supply I tested it during startup and it overshoots badly.? Enclosed are some of the startup scope traces I took.? I am working on a circuit that will replace the neon tube with a 50V Zener in series with a TL431.? Since the 50V Zener will be inside the control loop its temp coefficient will not be an issue.? I will publish the TL431 design later in the week.? ? Mike ? From: [email protected] <[email protected]> On Behalf Of Bill Berzinskas
Sent: Friday, September 20, 2024 11:30 AM To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed ? CONV mode is the only functional mode, i get blooming at almost any intensity / persistence setting in storage mode unless its so low its basically OFF.? ? ? ?? ? On Fri, Sep 20, 2024 at 12:21?PM factory via <bobradios11=[email protected]> wrote:
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