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Would welcomee anyone sharing their experience with Solen MKP crossover caps and if they should be replaced after 35 years.

I have a pair of the these, now 35 years old. The sound has deteriorated to the point that Jim Reeves sounds very nasal & thin, horns and percussions are hurting to the ears. Removed the crossover board and note that its populated with Solen MKP Film caps which seem to be in good condition...

I received a PA amp (Australia Monitor SY400) which has +4.9mV (Right) and -9.7mV (Left). Is negative DC offset (although very small) a thing to be worried about? What could cause a negative DC offset reading? Thanks in advance.

Sorry I did not include this observation earlier : When the wall power is switched on after the "2 hour rest", the receiver immediately switches on by itself, even if the "On/Off" button on the receiver has not been pressed and all previous settings, including radio station presets are erased...

It holds the settings for about 2 hours after wall switch or the on/off button is used to turn off the power. When the set is switched on after 2 hours, the "All Clear" is displayed and whatever previous settings, including FM presets are erased.

Thanks. Perhaps I should re start this thread in the "Tubes" forum.

Hope one of the experts can chime in. Thanks.

FX Audio offers two separate tube pre amps. One uses the 6j1 tube the other uses 6k4. Am interested to know what differences there are between these two tubes. Thanks. Robert

You can but they will just fry right up again. Dim bulb will stay bright all the time. Use a low wattage bulb (say 40 Watts) in the dim bulb tester. The board is unlikely to burn but the dim bulb may remain bright, indicating that a short still exists.

My Sony displays an "ALL CLEAR" message when the wall power switch is turned on. All previous Settings are also erased and the AV Receiver is back at default settings. Is there a battery, capacitor or something else supporting the memory and the settings entered? If so, please help to identify...

Am out of town for a few days. Will attempt your fix later this week. So does this mean that the high 9V Vbe of Board 2760 does not damage the KSA992 (which has a max of only 5V Vbe)?

Sansui AU217 - Having problems using 2x KSA992 to replace each 2SA798. I have perfectly matched KSA992s and soldered them to Board 2760. However, DC actually incrreased fluctuating from 0.8V to 30V. Thinking that I did something wrong, I made another matched pair of 2 x KSA992 and fitted...

I replaced TR11 shortly after Post #4. Thanks for the advise on blackened transistor legs.

From Board F-2758, I pulled out Transistors TR01 to TR04 and noted that the E-C-B legs of each transistor were completely blacked and rough on the surface. Does this mean these transistors are failing? In addition, the hFE readings were way below the Min 55 as given in their datasheet. I...

TR12 & TR11 are 2SC711, not 2SA711 as described above.

Hi John, They are connected correctly as (I I) As seen from top. And the emitters are in the same hole. I traced the fluctuating DC all the way back to TR12 (2SA711). It had a very low 210 hFE vs data sheet of Min 300. As soon as the A711 was replaced with KSC1845FTA, the DC stabilised and...

Sorry, some confusion in the way the hFE reading were displayed in my Post #1 above. They should read as : 2SA798 : hFE for B1-C1-E = 434; hFE for B2-C2- = 428 (Looks pretty good and ties with spec sheet). 2 x KSA992 : hFE for B1-C1-E = 358; hFE for B2-C2-E = 343 Thanks Robert

I recapped & replaced all resistors to 1% metal film a few years ago and the amp has been for a few hours daily. Recently, the right channel had been slightly softer and a quick check showed that the DC offset in this channel is fluctuating between 20mv and 600mv. I have read frequently that...

On the FX Audio 6j1-03 (with tone controls) why is there an opamp next to each tube? Is the tube functioning to its full extent ... or is the opamp "supporting" the tube in some way? However, in the FX Audio 6j-01 version, there are no such opamps (that I can see).

Late last year, after reading all the glowing reviews on the new NAD C3-- series, I went to the local dealer with high expectations and ... Was thoroughly disappointed. No new NADs for the time being.

The random popping noises could well point to failing small value transistors. And together with a good recap job and calibration, this will be a definite keeper.

Ive had a pair of SP-L150s which I bought new in 1978, together with an AU217 and TU217. Great combination. It's still with me now. Replaced the woofer surrounds with rubber (not foam) about 12 years ago. In mid 2017, I recapped the 2nd Order 12db crossover and replaced the internal wires...

Could the above problem be due to some resistors (that test good on the DMM) but fail under full load? I have read that aging resistors (especially cc) fluctuate in value as its temperature changes inside of a working amp. Hope the gurus here can help to shed some light on this.

Sometimes crossover resistors may not show any physical damage but still not work. Since they are not expensive, might as well replace the resistors when doing the capacitors. It will save you another round of dismantling. Cheers.