Posts by krais (archived2)
146 total posts136 results
BM8000 - Strange problem
in Imported Content (Unmapped) · Jan 16, 2022 11:58Hi Christian Thanks for the warning, yes I'm aware of the dangers of high voltage. I already had replaced the AC line capacitor with a new X2 safety cap when repairing the BM8000 a while back. I double checked and it mea…
BM8000 - Strange problem
in Imported Content (Unmapped) · Jan 15, 2022 11:30Hey everyone, a while a go my BM8000 that had been working perfectly for about a year all of a sudden started acting up. When I turned on the Beomaster, I heard a loud thumping noise when turning the volume wheel (low vo…
Question on Beomaster 4400 cabinet restoration
in Imported Content (Unmapped) · Aug 16, 2021 12:29Thanks all, here's a quick update. I was able to sand down the scratch as it wasn't very deep. I used some epoxy with sanding dust to fill a small dent and sanded the surface using 220/280/400 grit. After applying multip…
Question on Beomaster 4400 cabinet restoration
in Imported Content (Unmapped) · Jul 16, 2021 18:17Hi everyone, I have a Beomaster 4400 in pretty good condition but with some light scratches in the top cabinet. The plan is to carefully sand the cabinet and apply boiled linseed oil to bring it back to original conditio…
Beomaster 1500 - DC offset problem
in Imported Content (Unmapped) · Jun 25, 2021 12:00Thanks Martin! I'll take a stab at repairing the potentiometer using this method.
Beomaster 1500 - DC offset problem
in Imported Content (Unmapped) · Jun 22, 2021 21:14Found the problem... Very much ashamed to admit it, but my previous statement that the bass/treble potentiometers measured ok turned out to be incorrect. The problem is the bass potentiometer: the resistive strip does no…
Beomaster 1500 - DC offset problem
in Imported Content (Unmapped) · Jun 20, 2021 21:40The C111/C211 electrolytic caps measure as follows: C111: 2.03 uF, 6.98 ohm ESR @ 1KHz C211: 1.94 uF, 8.27 ohm ESR @ 1KHz Thanks for the info on the XJW01. I considered a DE5000 but that was a little beyond my budget (wi…
Beomaster 1500 - DC offset problem
in Imported Content (Unmapped) · Jun 19, 2021 19:14[quote user="Dillen"]Are C117/C217 new? If not, I suggest you replace them. Ideally also C111/C211/C121/C221.[/quote] Thanks Martin. Yes, C110/210, C111/211, C117/217, C120/220, C121/221, C122/222 are all new.
Beomaster 1500 - DC offset problem
in Imported Content (Unmapped) · Jun 19, 2021 19:13[quote user="Dillen"]Are C117/C217 new? If not, I suggest you replace them. Ideally also C111/C211/C121/C221.[/quote] Thanks Martin. Yes, C110/210, C111/211, C117/217, C120/220, C121/221, C122/222 are all new.
Beomaster 1500 - DC offset problem
in Imported Content (Unmapped) · Jun 19, 2021 19:09This is awesome, thanks so much! [quote user="manfy"]So, I'd say we forget about fine-tuning the caps for now and look at the output transistors TR101/201.[/quote] I already tried replacing TR101/201 with matched transis…
Beomaster 1500 - DC offset problem
in Imported Content (Unmapped) · Jun 18, 2021 22:03Thanks! Here are the values: C112 9.94 nF C114 10.17 nF C212 10.01 nF C214 10.27 nF C115 68.73 nF C116 67.98 nF C215 70.65 nF C216 68.58 nF
Beomaster 1500 - DC offset problem
in Imported Content (Unmapped) · Jun 17, 2021 18:44[quote user="manfy"]Is that channel imbalance audible in the speakers? How far do you have to push the balance slider to get a balanced signal on both channels (according to the multimeter)?[/quote] The imbalance is not …
Beomaster 1500 - DC offset problem
in Imported Content (Unmapped) · Jun 16, 2021 20:21I've checked the treble and bass potentiometers for corrosion but they seem fine. The electrolytic caps in the preamp circuit already have been replaced and I could not find any obvious faults when measuring the other co…
Beomaster 1500 - DC offset problem
in Imported Content (Unmapped) · Jun 16, 2021 20:13No worries Manfy and thanks to you and Martin for the quick help. I did run into another problem with the BM1500 though... When testing the output amps I noticed that the amplitude of the left channel is around 25% highe…
Beomaster 1500 - DC offset problem
in Imported Content (Unmapped) · Jun 1, 2021 11:38hfe for the BC547B's measured around 400, so I figured that might be ok (given the service manual listed a BC547B as well). But yeah, I can definitely swap them for BC547C's or just put back the originals. It does not se…
Beomaster 1500 - DC offset problem
in Imported Content (Unmapped) · Jun 1, 2021 10:31Oops typo, sorry for the confusion. The replacement transistors I used are BC547B, not BC548B. The originals were all BC547C even though the service manual lists BC547B for 6TR104/204 and BC182C for 6TR105/205.
Beomaster 1500 - DC offset problem
in Imported Content (Unmapped) · May 31, 2021 20:34Hi folks, I'm currently restoring a Beomaster 1500 and ran into a mysterious DC offset problem. Originally DC offset measured a little high (around 15mV on both channels), so I decided to replace transistors TR104/105 an…
Beomaster 4400 - placement of R40
in Imported Content (Unmapped) · Mar 7, 2021 09:09Thanks Martin, Sonavor!
Beomaster 4400 - placement of R40
in Imported Content (Unmapped) · Mar 6, 2021 22:07Hi guys, I'm currently restoring a Beomaster 4400 and have a question on R40. On my unit this thermistor is floating in the air, well clear of the heatsink. Isn't this thermistor supposed to be attached to the heatsink, …
Voltage rating for coupling capacitors in preamp, tone control circuit
in Imported Content (Unmapped) · Feb 6, 2021 10:59I'm currently restoring and recapping a Beomaster 4400. In the preamp and tone control circuits many of the coupling capacitors are rated 1uF 63V, 2.2 uF 63V and I'm wondering why the voltage ratings is that high for low…