Beomaster 2400 Type 2902 - Canada Project Capacitor Replacement Part 2

Wrapping up the Beomaster 2400 capacitor replacement is just recapping the tone, filter and FM tuning board. Just eight capacitors on this board. This board also has the three slider controls that I cleaned with Deoxit fader lube. 

Here is the board before replacing the capacitors.

Here is the board after the recap. As with the other boards, the seven electrolytic capacitors were way out of tolerance (50% to 100% off their value). The lone 0.22uF tantalum was fine but in being consistent with my other replacements I replaced it with a WIMA MKS capacitor.

All total, there were 58 electrolytic capacitors and 19 tantalum capacitors replaced in this Beomaster.

Beomaster 2400 Type 2902 - Canada Project Capacitor Replacement Part 1

 I got through all of the work replacing old capacitors in the Beomaster 2400 main board (over 60 capacitors) and volume control board (2 capacitors).

Here is the Beomaster 2400 again prior to replacing the electrolytic capacitors.

This restoration was different than my usual Beomaster 2400 capacitor restorations.
The owner of this Beomaster had already purchased a Beomaster 2400 recapping kit from Martin Olsen.  It has been a long time since I used someone's capacitor kit but why not? The capacitors are good capacitors so I wouldn't want to waste them.

Martin's kit also included a new bridge diode for the incoming AC power so I will replace that.
This kit has all of the replacement capacitors for the Beomaster 2400 electrolytic capacitors except the two large 5000uF, 50V reservoir capacitors so I will add those two.

The kit also does not contain replacements for the Beomaster 2400 tantalum capacitors. The tantalum capacitors are typically still okay but I normally replace them as the restored audio component often has a long trip back to its owner. Replacing them is a bit of additional insurance to avoid having to send a problem component back and forth.

Of course you will find a lot of discussion on various audio forums about whether to replace tantalum capacitors with tantalums or a different type like electrolytic or polyester.  For capacitance values of 4.7uF and smaller I prefer using WIMA MKS polyester capacitors so that is what I will be doing here.

Here is the Beomaster 2400 after the recapping task of the main board and volume control board have been completed.

I also replaced the left and right channel no-load current adjustment trimmers with new multi-turn, sealed type trimmers.  There were three capacitors, the black ones in the photo, that were capacitors that had been replaced by someone else previously.  They measured good but I changed them so that all of the capacitors starting with this restoration are the same age. One thing to note...one of the previously changed capacitors was 33uF instead of the original 22uF capacitance value.  Martin's kit calls for the original 22uF capacitor which is also what I have always used. I have no idea why the 33uF was put in here.

For my own knowledge base I always take a little extra time and measure each capacitor I remove. I just want to know what state it is actually in.  On this Beomaster 2400 all of the electrolytic capacitors except the large ones were out of tolerance. The 1uF capacitors almost all measured over 2uF. The 2.2uF capacitors were either at 3.5uF or just over 4uF.  The 4.7uf were around 6uF. 

The tantalums were all still within their 20% tolerances but a lot of them were close to the upper limit.

The reservoir capacitors measured good but I still always replace them to insure against future problems.

Here are the two reservoir capacitors before replacing them.

Here is the after photo.

 

The reservoir capacitors are a little tricky to change. B&O connected a number of ground wires to the common point of the reservoir capacitors. The positive and negative DC connection points each have three wires connected as well. New power supply capacitors I use have small posts so connecting the number of wired the Beomaster requires means creating some good terminal solder points.

I joined two terminal posts together for the ground wires and soldered all of the ground wires to that ground terminal. I soldered the positive DC voltage wires to another terminal then soldered that to the positive post of the reservoir capacitor assembly. I also connected the negative DC voltage wires to a terminal on the negative post.

That makes for a really solid reservoir capacitor assembly and the wires are neatly connected.

Two of the black ground wires go to the speaker jacks.  The original wires are short and don't have much room to operate with.  One usually always breaks off when raising and lowering the main board during the recapping process. I always replace those with some longer wires that can handle the main board raising and lowering.

Here are the before and after photos of the volume control board.

Here is a photo of the two new multi-turn, sealed trimmers that will be used to adjust the no-load current of the output amplifiers.

The adjustment knobs for the trimmers are easier to access than the old trimmers.

The next restorations task is to do the capacitor replacement on the removable board with the tone controls, filters and FM tuning.  That will be followed by cleaning the slider controls and the replacement of the lamps.

Beogram 4002 Type 5513: Inside Work

The restoration of the Beogram 4002 from Houston continues as I worked on the inside of the turntable. In this post I worked on the tangential arm assembly components and the Beogram reservoir capacitor replacement.

Here is an updated photo of this Beogram 4002 with its chassis and tangential arm assembly removed.

The tangential arm assembly components on this Beogram 4002 are in excellent shape.  Most of my tasks were just cleaning and lubrication the Beogram chassis parts. In the photo above you can see the arm lowering damper removed and disassembled. The parts were nice and clean but the lubrication fluid for the damper was gone. I applied a fresh coat of PMX-200 silicone fluid per the service manual. The tangential drive spindle was also cleaned and lubricated along with the nylon nut (that drives the arm assembly). The tangential arm assembly tracking components were checked and all looked to be in great shape.

Two components I did change out were the tangential arm assembly position sensor lamp and the tangential drive pulley.

I replaced the old plastic pulley with a new aluminum one.

Just for reference here is a photo of the underneath side of the Beogram 4002 tangential arm assembly carriage. It isn't seen very often in restoration photos but is a good thing to examine.
The thin wires from the phono cartridge come out of the base of the tonearm pivot and connect to a transfer board. From there they are picked up by a larger, shielded cable that takes the audio signals over to the audio muting circuit just prior to exiting the Beogram (to a preamplifier).

....and finally here is a photo of the new Beogram 4002 reservoir capacitors. As usual I installed the nice Beolover replacement capacitor assembly.

There were no surprises with this Beogram 4002 turntable and these components are now ready to be reassembled back in the Beogram cabinet.

Beomaster 1900 Type 2904: Capacitors replacement Part 1

Most of the electrolytic and tantalum capacitors have been replaced on this Beomaster 1900 now. That replacement was long over due and badly needed. Over eighty percent of the capacitors I replaced measured out of tolerance or completely dead.

I will start with a couple of pictures showing the recapped main board.

Being packaged into such a low profile cabinet the Beomaster 1900 circuitry is mostly on one big board (labeled module 2 in the service manual).  There are a few other small boards with a few electrolytic and tantalum capacitors but the majority of the task is the large module 2 board.

The capacitor replacement was pretty standard....desoldering, measuring and replacing one capacitor at a time. It takes extra time to measure the old and new capacitors but I like to know that information on each restoration.

The Beomaster 1900 did have a couple of capacitor replacement tasks that took some extra work.

The reservoir capacitors 0C7 and 0C8 don't have a bracket to hold them and utilize the original capacitor's large, flat terminals to connect up all of the ground and power lines to them.

To make that task a little easier I mounted a terminal between the two grounded posts of the new reservoir capacitors to secure them together. I also added multi-tab terminals to the two posts for the power wires.

This Beomaster 1900 has a modification not shown in my service manual in the left and right volume related circuitry. This board wasn't in the previous Beomaster 1900 project I did.

This picture shows the small mod board attached to the main board.

There is one lone tantalum capacitor in the FM tuner (metal) box that I replaced.

The volume control board has two small tantalum capacitors that I also replaced.

The last couple of pictures show the replacement of the +15VDC power supply capacitor 2C92.

That just leaves the capacitors on the tone control and FM tuning control boards. I will show that on the next blog post for this project.

Texas Beomaster 8000: Big update

Today I got the Texas Beomaster 8000 project caught up to where the Canada Beomaster 8000 project is. Both receivers now have reworked output amplifier board assemblies, reservoir capacitors, speaker switches and power supply boards. Both units also needed cabinet and frame treatments to get back to like new condition. All of those tasks are now reassembled into each Beomaster.

Here is the current state of the Beomaster 8000 from Texas.

The road to this point in the restoration was similar to that of the Beomaster 8000 from Canada.  The bottom plates of the cabinet didn't have any rust but they were quite dirty and had places where bare metal was exposed. So like the previous Beomaster 8000 I took everything apart, cleaned and repainted the base plates.

Here are the base plates repainted.

Next I replaced the reservoir capacitors, changing out the original ones for Beolover replacement reservoir capacitors.

Here is the Beomaster 8000 frame with the reservoir capacitors removed.

Here are the new, Beolover replacement parts next to the original capacitors. You can see that the Beolover 3D printed housing retains the original size which is important in accurately rebuilding the Beomaster 8000.

Here are the new left and right channel reservoir capacitors. I am leaving the wires for the left channel reservoir capacitors disconnected for now so the wires have enough play in them for the left channel output amplifier assembly installation.

While the Beomaster frame still has the base plates removed I will update the two speaker switches. It is easier to work on those with most of the components out of the way.

Here are the two original speaker switches.

Here are the two new speaker switches with the Beolover 3D printed base (so they will fit properly).

Now I can turn the Beomaster frame upside down to reinstall the cleaned and repainted base plates.

It looks quite nice if I do say so myself. There is an extra good feeling you get when everything is new and clean. The Beomaster begins to feel like it is going through the factory as a new creation...even though it is almost forty years old.

Now for the reinstallation of the output amplifier board assemblies. As usual I start with the more difficult left channel.

Turning the Beomaster cabinet back over...

You may have noticed that this time I rotated the output amplifier board 90° the opposite way than I did on the previous Beomaster 8000 left channel output amplifier installation. I am still deciding which way I like best. This time seemed like it was easier but it could just be that I am getting the hang of it. In any case this beats my original method of attaching the heatsink mounted components after installing the amplifier board.

The left channel output amplifier assembly is mounted in place so I can complete the left channel reservoir capacitor wiring now.

Next up is the right channel output amplifier installation. The 90° board rotation technique would work here but I have been able to reinstall the board without turning it.

The final step of this install is to secure the back panel to the heat sinks.

The last task in the restoration catch up is to clean and recap the power supply board. That includes the small heat sink with the voltage regulators.

This power supply board was pretty dirty. It has also been worked on before. The C51 1uF capacitor had been replaced by a 2.2uF capacitor for some reason. I will put everything back to the values that are supposed to be there.

Here is the board with the parts I will replace removed.

Here is the board after an alcohol bath.

When I examined the trace side I found a couple of areas that needed addressing. The solder joints in the middle of the board did not look good. They weren't smooth.

I don't know what was going on there so I de-soldered the ones that looked bad, cleaned up the area and resoldered it.

I also found a trace that was almost broken through.

I scraped away more of the coating to get to the copper trace and used a small piece of magnet wire for the repair.

After the cleaning and solder repair I installed the new capacitors. On the three large capacitors I added a bead of black hot glue to help secure the axial capacitors.  This type of glue works good in this application and can be removed in the future the next time this board requires rebuilding ... 2058? ...I don't think I will still be around :-) .

Here is the completed power supply assembly.  I replaced the thermal insulators on the voltage regulators with Sil-Pads.

I will leave the shield box top and bottom pieces off for now until I can test that the remote control capabilities work.

There is the power supply assembly back in the Beomaster cabinet. This is a major milestone in the restoration of these two Beomaster 8000 units. The next task is to recap the Preamplifier board and the Filter & Tone Control board.