Beomaster 1900 Replacement Reservoir Caps

12 replies
T(
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tom79 (archived2)
Bronze
Posted October 8, 2020 at 19:22 GMT
#2212262

Hi all!

I recenently purchased a used Beomaster 1900 (Type 2903) receiver. I am now in the process of recapping it to get rid of the quite noticable humming.

Since I have no experience in repairing hifi components, I bought the recap kit from the beoparts shop to make my life easier.

After dismantling the amplifier, I noted that one of the two large reservoir caps had leaked. The reservoir caps were not part of the aforementioned recap kit, so I now have to find an adequate replacement myself. Which brings me to my main question:

I am totally overwhelmed which ones to buy. The original Wilcon caps were rated 5000 uF at 35V. It doesn't say much more on the tin and I can't find the full specs anywhere. I only found one blog article where a specific replacement cap was mentioned (

T(
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tom79 (archived2)
Bronze
Posted October 9, 2020 at 15:07 GMT
#2212263

Martin,

thank you so much for your help!

I just ordered two Vishay 2222 056 57472 caps which seem to meet all of the specs you mentioned. I can't wait to have my Beomaster working again.

Have a nice weekend!

 

Tom

DI
Offline
Dillen
BronzeModeratorFounder
Posted October 9, 2020 at 15:48 GMT
#2212264

Except the data-sheet says Low ESR...

https://www.vishay.com/docs/28340/056057psmsi.pdf
2nd line.

Risk of selfoscillation.
Been there, hence my note.

Martin

T(
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tom79 (archived2)
Bronze
Posted October 9, 2020 at 23:52 GMT
#2212265

Hi Martin!

Now I'm slightly more confused. When I researched the cap, I referred to link, which is for the same cap series but older (anno 2005). Unlike the newer datasheet, it doesn't mention low ESR anywhere, despite having the same ESR values listed as in the newer datasheet.

I also checked the caps from the 058 series (), which were explicitly labeled as "low ESR". So I went for the 056 series.

It seems like the manufacturer has changed their definition of "low ESR" over the course of time.

 

The 056 series cap in the 25x30mm case size has an ESR of 82 mOhm at 100khz (4700uF, 40V). This is the case size I ordered.

The same 056 series cap in the 22x40mm case size has about half the ESR (49 mOhm).

 

So my question: What ESR values should I be looking at to be considered "not low ESR" ?

 

Sorry for being overly curious, but I just want to make sure that I put in the proper caps before I go through the long process of reassembling the 1900.

 

Cheers,

Tom

FK
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fkatze
Bronze
Posted October 10, 2020 at 14:16 GMT
#2212266

Cheap general purpose (black) Nichicons will more than likely suit.

T(
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tom79 (archived2)
Bronze
Posted October 10, 2020 at 17:44 GMT
#2212267

Thanks!

I've now picked the Nichicon LGU1V472MELA. I hope these will be fine.

 

Have a great weekend!

Tom

T(
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tom79 (archived2)
Bronze
Posted October 14, 2020 at 23:46 GMT
#2212268

Hi all!

I am happy to report that the recap was successful. Now the old lady sound like it's 1976 again :-)

 

Thanks to Martin and fkatze for your support!


Tom

A(
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aschenbrenner (archived2)
Bronze
Posted December 1, 2020 at 22:10 GMT
#2212269

Hi Martin, what happens if you use the wrong capacitor ?

DI
Offline
Dillen
BronzeModeratorFounder
Posted December 2, 2020 at 06:35 GMT
#2212270

The Beomaster was constructed with the type of components that were used in production in mind.
If you change a component to one of a different type, you will often get a malfunction - like if you replace the front panel incandescent lamps with LEDs or a wrong type of lamps, the related functions will no longer work as intended.

If you fit low-ESR capacitors or high-HFE transistors in the output stage, there will be a risk of self-oscillation.
If you fit low-ESR capacitors for the power supply filters, the same can happen - and you will place more stress on the rectifier, because of the very low  impedance of the capacitors at power up (when charging begins).
Do both and you are almost guaranteed to blow something - either the output stage or your tweeters.

We had this (small) example not to long ago:

A(
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aschenbrenner (archived2)
Bronze
Posted December 2, 2020 at 07:57 GMT
#2212271

I see, does this also cause the popping sound when turning on ? 

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