Whither the capacitors?

[DigaDo]

There have been a number of posts in this and other threads or forums that mention failed or failing power supply capacitors in Panasonic DVD recorders, combo recorders and hard drive recorders. Some of these posts are mine.

With my (2006 model) DMR-ES35V combo recorders and DMR-ES15 DVD recorders I have found that the culprit is the largest electrolytic capacitor in the power supply section.

With DMR-ES35V models the power supply is part of the right chassis motherboard; with a DMR-ES15 the power supply is part of the main chassis motherboard. Replacement requires extensive disassembly. The whole procedure takes one hour + per machine.

The largest electrolytic capacitor in the power supply sections in DMR-ES15 and DMR-ES35V models are not of the same specification. In a DMR-ES15 model C1143 is 100uf 350v. In a DMR-ES35V model C11108 is 220uf 250v. Both have a heat range of 105 C degrees, and are 30mm tall. I ordered replacement capacitors for both models through a local electronic parts store. These capacitors have the same specification as those used by Panasonic but they are from a different manufacturer.

In February 2008 I replaced the leaking power supply capacitors in three of my four DMR-ES15 models. The recording hours for the four DMR-ES15 models is (currently) 2,966, 988, 330 and 845, respectively. My fourth DMR-ES15, the one with 845 recording hours, continues in daily use with its original capacitor that did not evidence leakage at the machine's most recent DVD drive service.

After capacitor replacement all three of the DMR-ES15 models checked out OK; two were placed into regular daily service (one for a month or so) and the third, the one with but 330 recording hours, was set aside for standby use.

In the last week one of those DMR-ES15 models that had capacitor replacement in February had experienced a recording failure and was removed from service. The second DMR-ES15 that had capacitor replacement in February was swapped in to replace the machine with the recording failure. That machine had no difficulty recording but it is unable to finalize a disc so it was also removed from service. (The disc was finalized on the DMR-ES15 that remains functional.) The third DMR-ES15 that had capacitor replacement in February was then swapped in but it was found to be “dead” (a common indication of capacitor failure). Today my original DMR-ES30V (in semi-retirement with 4,212 recording hours) was put back into daily service.

I also own four DMR-ES35V models. Three of the four evidence leakage from the largest electrolytic capacitor in the power supply. Those models were set aside for capacitor replacement in January/February 2008 but I have not had an opportunity to replace the capacitors in the those three models. The recording hours for the four DMR-ES35V models is (currently) 2,985, 3,140, 3,065 and 480, respectively. My fourth DMR-ES35V, the one with 480 recording hours, continues in daily use with its original capacitor that did not evidence leakage at the machine's most recent DVD drive service.

I also own two DMR-ES30V models. These 2005 models differ from the 2006 models in that two large (matching) electrolytic capacitors are used in the power supply section that is mounted on a platform at the rear of the case. The recording hours for these two DMR-ES30V models is (currently) 4,212 and 2,680, respectively. (Neither DMR-ES30V evidenced capacitor leakage at its most recent DVD drive service.

Some of my Panasonics were purchased new, some were purchased refurbished (by Panasonic) and some were purchased used. When I mention “recording hours” these figures are from recording utilization records I maintain for machines while they are in my service.

[DigaDo]

Replacing Panasonic capacitors yourself? Some advice:

If your Panasonic is still functional but has experienced some operational or performance problems it may be due to impending failure in power supply capacitors.

Other failures may be due to the need for DVD drive hub/spindle cleaning. See the first post in the below linked thread. That post has links to general hub/spindle cleaning advice, the cleaning procedure itself and other links addressing possible reassembly complications:

http://www.avsforum.com/avs-vb/showthread.php?t=1055071

I will offer observations and advice based upon my experience in replacing electrolytic capacitors in several of my Panasonics. I must add that electronics is not my field so the advice that follows might need correction from someone experienced in that field.

The Panasonic power supply is located close to the AC cord connection on the rear panel. Be sure to check the nearby fuse if your Panasonic is dead. If the fuse has blown it is inexpensive and easy to replace. If a power supply capacitor has failed the Panasonic may be dead for that reason as well.

Capacitors store an electronic charge. That is reason enough to disconnect the AC cord well in advance of the procedure to allow the capacitor to lose its charge. Exercise caution when working in and around the power supply, even after the power has been disconnected.

If the Panasonic is operational but experiencing problems it is likely that one or more power supply capacitors are beginning to fail. The power supply will have electrolytic capacitors (a canister) and “chubby disc” type capacitors (a smaller device standing on two legs). Electrolytic capacitors are black or dark brown jacketed canisters with an aluminum top and a grey stripe running down one side. The grey stripe indicates the capacitor’s polarity. The leakage may appear as bubbly ooze on the capacitor’s side or around the capacitor’s base and on the circuit board. This leakage will probably be somewhat hardened rather than pliable or moist. “Chubby disc” type capacitors may be beige or brown. These demonstrate impending problems with bloating or leakage.

Some capacitors may continue to function during early stages of failure but any leakage or bloating indicates that the Panasonic is operating on borrowed time.

Some Panasonics have the power supply section on a separate circuit board. That simplifies capacitor replacement because extensive disassembly is not necessary. Other Panasonics have one or two large chassis motherboards that incorporate the power supply into the circuit board. These models require much more extensive disassembly. Allow at least one hour for the procedure.

During disassembly lay out all the various parts in an orderly manner so they may be correctly reassembled following the procedure. Several parts assemblies and the chassis motherboard itself will need to be removed in order to gain access to the back side of the circuit board for the soldering process. Some motherboard or other circuit boards may have ribbon cables or conductive bridge connectors between these circuit boards. Gently disconnect these by grasping the plug portion from the ends. Ribbon cables may have reinforced tabs near their ends to allow easier withdrawal and insertion.

In most models it may be necessary to remove the front panel; the hard drive and its cables/connections (if so equipped); the DVD drive and the DVD controller circuit board assembly and its cables/connections; many of the screws securing the rear panel to the tuner, I/O jacks, AC power connector, etc.; possibly the fan; those motherboard screws indicated by the adjacent screw icon; a mini-switch circuit board in some models; and in some models the central anchoring screw found recessed into the motherboard’s front input jack assembly. Then the motherboard itself may be lifted off its small blade type guides and removed from the chassis.

The specification of electrolytic capacitors will be found on its side. This will include specifications for uF, V, and the degree range. You may wish to measure the physical height as an additional specification. Some Panasonic low-profile cases may limit capacitor height. A capacitor more than 30mm or so may be too tall to fit some models.

Capacitors are generic so it is not necessary to order these from Panasonic. A local electronics parts store may have them or be able to special order them. Unsolder the old capacitor and take it with you to the electronic parts store so they may identify and order the correct specification replacement (if they do not have the right capacitor in stock).

Make a notation of the position of grey stripe (indicating polarity) so the new capacitor may be oriented the same way. The polarity may also be indicated on the circuit board. When unsoldering the capacitor from the back side of the circuit board take care to pull the capacitor straight off the front side of the circuit board after heating both soldered areas around the pins on the back side. Do not rock the capacitor as that may loosen or damage the “foil” covering carrying the circuitry on the back side of the motherboard. (If the “foil” lifts somewhat that does not necessarily mean that the repair has failed. This is just meant as a caution.) Electrolytic capacitor removal may be somewhat difficult as the electrolyte leakage itself forms somewhat of a bond to the motherboard. Carefully remove the residual leakage from the front side of the motherboard and clean the area with Isopropyl Alcohol. Guide the new capacitor’s pins through the holes, heating the solder to allow insertion, if necessary, making sure not to loosen or damage the “foil” on the back of the motherboard. Be sure to reheat the existing solder or use very little new solder until the solder flows smoothly around the pins, taking care not to allow any excess amount to intrude upon another circuit or another component’s solder or pins. Trim off the excess pin length after the solder has cooled.

Reassemble the Panasonic. If the Panasonic has a VHS section take care to hold the VHS door open as the front panel is being fitted back to the case. This will assure the correct alignment of the VHS door lifting mechanism.

[DigaDo]

Here are two photos showing leakage of the largest electrolytic capacitor in one of my still-functional DMR-ES35V combo recorders. This Panasonic was set aside for capacitor replacement in February. The second photo will give one a view of some of the parts necessary to be removed, including the right chassis motherboard itself, in order to replace the leaking capacitor. In the foreground notice the conductive bridges between the left and right chassis motherboards.

I expect to take step-by-step photos the next time I have capacitor replacement session(s). Due to extensive disassembly, capacitor replacement occupies somewhat more than one hour per machine.

Six of my 2006 model year Panasonics have been set aside awaiting capacitor replacement. Three are DMR-ES35V combo recorders and three are DMR-ES15 DVD recorders.

[Bunny]

Nice pictures there DigaDo.
In the picture of the main power supply capacitor. That is not electrolyte leakage you are seeing, that is a resin applied by the manufacturer to make sure the capacitor stays firmly seated to the P.C.B. You can clearly see the resin on the side of the capacitor. A capacitor cannot leak from the side, it is a solid metal can. If electrolyte does leak from an electrolytic capacitor it will leak underneath at the opening in the can where the legs of capacitor emerge.

Also the voltage on that capacitor can remain at over 300 Volts with the power cord removed for days. So be careful as you can really get a nasty shock or ground the voltage through the power supply circuit when you apply the soldering bolt can take out the power supply.

[DigaDo]

[QUOTE=Bunny;2119534]Nice pictures there DigaDo.
In the picture of the main power supply capacitor. That is not electrolyte leakage you are seeing, that is a resin applied by the manufacturer to make sure the capacitor stays firmly seated to the P.C.B. You can clearly see the resin on the side of the capacitor. A capacitor cannot leak from the side, it is a solid metal can. If electrolyte does leak from an electrolytic capacitor it will leak underneath at the opening in the can where the legs of capacitor emerge.

Also the voltage on that capacitor can remain at over 300 Volts with the power cord removed for days. So be careful as you can really get a nasty shock or ground the voltage through the power supply circuit when you apply the soldering bolt can take out the power supply.[/QUOTE]

Bunny,

Thank you for correcting and clarifying these matters. Electronics is not my field so my posts were based upon some others that described machine failures, observation of failed disc-type capacitors, replacement of those failed or failing capacitors, and the return to functionality of various other Panasonic models.

My observation of the resin bonding agent was misinterpreted by me as electrolyte leakage. My replacement of these power supply capacitors in still-functional machines was deemed by me to be “preventative maintenance.”

I opened my other two set-aside DMR-ES35V models to re-examine this capacitor. Both appeared very much the same as did the first machine shown in my earlier photos.

In the below photo the three capacitors on the left were removed from three of my DMR-ES15 models. The capacitor on the right was removed from a non-functional DMR-ES35V parts machine.

After capacitor removal most of the beige material was peeled off the capacitors and the chassis motherboard was cleaned of the residue before installation of new capacitors.

On the DMR-ES35V capacitor the residue was of lighter beige than that on the DMR-ES15 capacitors. Around that ES35 capacitor there was perhaps three times as much residue flowing outward from that capacitor than the residue shown in the earlier photos. The replacement capacitor in the ES35 parts machine was, for me, experimental, and did not remedy that machine’s problems.

As to my set-aside DMR-ES15 models, I expect to do more evaluation. I expect to return my three set-aside DMR-ES35V models to their regular rotation of duties. You have saved me a great deal of needless labor.

Thank you again!

[jjeff]

[quote=Bunny;2119534]Nice pictures there DigaDo.
In the picture of the main power supply capacitor. That is not electrolyte leakage you are seeing, that is a resin applied by the manufacturer to make sure the capacitor stays firmly seated to the P.C.B. You can clearly see the resin on the side of the capacitor. A capacitor cannot leak from the side, it is a solid metal can. If electrolyte does leak from an electrolytic capacitor it will leak underneath at the opening in the can where the legs of capacitor emerge.
[/quote]
I would have to agree with Bunny, from your photos I also thought it looked like glue that is applied to certain, mostly larger electronic parts when attached to a circuit board. Your reasoning makes sense that it is to secure the parts to the circuit board so they are not just held in place by the solder.

Digado, when I have seen old(50+) year old electrolytic capacitors leak, they usually show up as a white crusty substance, and Bunny would be correct in that they would show up on the bottom of the can and rarely if ever from the top or side. Some capacitors(old waxed ones come to mind) that have a waxy tan substance over them that look similar to your photos, although they really don’t leak but rather dry out and fail.
Maybe this explains why I haven’t seen any of my power supply capacitors leaking, although I believe you have seen some of your capacitors bulging which is really not a good sign. Haven’t you had machines not work and then you’ve replaced the capacitors and they work? If so I don’t think your capacitor replacement was unneeded because replacing good capacitors wouldn’t have had an effect on the operation of your machines.
P.S. Nice photos, it sure makes talking about something a lot clearer.