[TechAssist] Re: Realistic Stereo Receiver STA-2100
- From: Edward Gaidies <teltek@xxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Mon, 12 Nov 2001 21:08:37 -0500
Yes...Frank, you have.
This amp is so old, but the customer loves it, so I thought I'd do some real
troubleshooting.
Thanks;
-Ed-
>
> Check the emitter resistors on the output,(.33ohm or the like)Usually 5 or
> more watts. Also check the voltages on the base and emitters of the outputs
> with them in circuit. The base voltage should be around 1vdc+/-. Usually
> it's about 0.5vdc+/-. If it's higher start with the outputs. Pull out one
> at atime and check them for leakage. Work your way back up the signal path
> until you get to the amp input. If they all Check out then check resistors
> around the driver section and feedback section.
> Hope I've been of some help
> Frank
> ----- Original Message -----
> From: "Tel-Tek Electronics" <teltek@xxxxxxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Monday, November 12, 2001 3:57 PM
> Subject: [TechAssist] Re: Realistic Stereo Receiver STA-2100
>
>
>>
>> Thanks Frank;
>> I have isolated it to Right side.
>> If I remove the B+ from one side, (unit has two modules, relay will click
>> and good side will work).
>> Have checked the transistors on the defective side, 4 mounted on heat
> sink,
>> and small drivers on the same module. Have checked them in circuit, and
> are
>> not shorted, although not sure if one may be leaky.
>> Any thing I should look for.
>>
>> Thanks.
>>
>> -Ed-
>> teltek@xxxxxxxxxxx
>> TEL-TEK ELECTRONICS.
>>
>>
>>
>>
>>
>> ----- Original Message -----
>> From: "RS Tek Inc" <rstek@xxxxxxxxxx>
>> To: <techassist@xxxxxxxxxxxxx>
>> Sent: Monday, November 12, 2001 9:10 AM
>> Subject: [TechAssist] Re: Realistic Stereo Receiver STA-2100
>>
>>
>>>
>>> Check the power supply that runs the protection circuit. They can go
> bad,
>>> also the transistor that sinks the relay can open up as well. See if
> you
>>> have dc on the speaker contacts that feed the relay.
>>> Good Luck
>>> Frank
>>> ----- Original Message -----
>>> From: "Tel-Tek Electronics" <teltek@xxxxxxxxxxx>
>>> To: "AAAA TECH-ASSIST" <techassist@xxxxxxxxxxxxx>
>>> Sent: Monday, November 12, 2001 1:44 PM
>>> Subject: [TechAssist] Realistic Stereo Receiver STA-2100
>>>
>>>
>>>>
>>>> Anybody worked on these old Stereos.
>>>> Customer complained of relay cutting out periodically.
>>>> Now relay won't activate at all. All O/P transistors good. -57 and +57
>>> volts
>>>> on collectors. No fuses blown. Have 24 volts at relay coil. About all
> I
>>> can
>>>> say, since I have no Circuit for this.
>>>>
>>>> Thanks;
>>>>
>>>> -Ed-
>>>>
>>>>
>>>> teltek@xxxxxxxxxxx
>>>> TEL-TEK ELECTRONICS.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
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>>>
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>
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