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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 18th Sep 2020, 5:36 pm   #21
Edward Huggins
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Default Re: Brenell Purchases

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These were so well regarded in their day. You say yours are 4 speed. If the 4th speed is 15/16", I heard piano music very convincingly demonstrated on one of these at an early Hi Fi Show at the Russell Hotel, London.
The standard low speed is 1 7/8 ips, the top speed being 15 ips. There are 3 normal operating speeds, 15, 7 1/2 & 3 3/4 ips when using the large diameter (1") capstan sleeve. When using the small diameter (0.5") capstan sleeve the 3 speeds are 7 1/2, 3 3/4 & 1 7/8 ips.

David
Thanks for this useful clarification. I can only assume that Brenell machined a special capstan sleeve in order to make the Demo I heard.
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Old 18th Sep 2020, 6:39 pm   #22
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Default Re: Brenell Purchases

Had a quick look inside both of them by lifting out the amplifier modules.

Found all the valves are missing in both amps apart from the Magic Eyes. Think I should be able to find/borrow suitable valves from some of my other recorders but still a nuisance. The EZ80 full wave rectifier valve luckily is not missing from either power supply.
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Old 18th Sep 2020, 6:48 pm   #23
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Default Re: Brenell Purchases

To my best recollection, the only Brenell to offer 15/16ips was a special duty Type 19 military/Police voice/data loggers with reduced diameter capstan (some went down to 15/32ips; some up to 30ips).

Brenell made many specials but would never consider 15/16ips a worthy speed for music! I guess if you remove the capstan sleeve and run off the capstan you'll get close to 15/16ips.
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Old 18th Sep 2020, 6:57 pm   #24
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Does anybody know the purpose of the metal pillar on the right hand side of the adjustable tape guide, identified as "W. Supplementary Guide Pillar" in the Mk. 5 manual ?

David
It's meant to prevent tape spillage on start-up in Play.
Thank you Ted, so this photo I saw online has the tape incorrectly threaded around the outside of the pillar.

David
Indeed so. There is a similar post on the Collaro Studio, similarly abused.
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Old 18th Sep 2020, 8:13 pm   #25
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Default Re: Brenell Purchases

Some amplifier photos attached.

The Series 2 amplifier looks somewhat easier to work on, component access wise compared to the Mk. 5, there are several paper capacitors that will need checking before power is applied.
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Old 19th Sep 2020, 11:29 am   #26
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Default Re: Brenell Purchases

Been trying to remove the Series 2 tape deck from its case which requires the control knobs to be removed, to be able to remove that the top panel (Mask) to access the deck securing screws.

The Rewind control knob was loose on its control shaft, but would not come off. Found that the screwdriver slot for its securing grub screw is broken, after some struggling managed to extract the grub screw and pull off the knob. But the metal knurled insert from the knob has come out of the knob and is stuck on the rewind control shaft.

Really struggling to remove the insert from the shaft. It is strange because the insert will rotate fairly easily in both directions around the stationary shaft but will not budge at all when attempting to pull/lever the insert off the shaft ?

Do not want to use too much brute force in case the rewind control and/or the top panel get damaged.
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Old 19th Sep 2020, 12:56 pm   #27
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Default Re: Brenell Purchases

The grub screw had probably been loose and someone had screwed it around and cut a groove in the shaft which has a large burr. I think you may have to use a bit of force to lever it upwards. Put a piece of thin strong material, steel rule maybe to spread the force, and twist a flat screwdriver underneath the insert. Try to find the loosest place by rotating it first.
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Old 19th Sep 2020, 1:30 pm   #28
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Default Re: Brenell Purchases

Thank you. Rotating it either way there appeared to be no looser position.

Using more pulling force I got it off, the rewind control shaft is gouged up, will clean it up and the inner diameter of the insert and find a replacement grub screw.

David
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Old 19th Sep 2020, 1:47 pm   #29
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Default Re: Brenell Purchases

I think there are knob pullers used by guitar technicians... A sotted bit of flat steel with a cup ans a screw to press on the area around the knob.

David
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Old 19th Sep 2020, 5:53 pm   #30
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Default Re: Brenell Purchases

Tape deck and power supply removed from case.

The deck is solidly built and seems engineered well. There is some light brown sticky gunge around the metal hold down plates for the 4 motor suppressors (CR snubbers), not sure yet if leakage from the snubbers or residue of old oil/grease, will check them out electrically before applying power.

The spool motors are AEI BP1303B and the capstan motor which should be a Papst motor is a HMZ 14.50-4 675D

Will test the power supply out of the box, have seen the warning in the manual about not powering up off load.

Nice large elliptical Elac speaker inside the case.
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Old 20th Sep 2020, 9:00 am   #31
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Default Re: Brenell Purchases

Have been cleaning the tape path. As mentioned previously the R/P head is in a mess.

There is a hard black thick bumpy substance covering around 3/4 of the right hand face of the R/P head, no idea what it is. Am very slowly getting if off using cotton buds and IPA (Isopropyl alcohol) also trying Methylated Spirits. Will be interesting to see the condition of the head face underneath.

The heads should be Bogen, not sure if they are, they say "Hi Fidelity" on the top.
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Old 20th Sep 2020, 10:28 am   #32
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Have tested the power supply off load. Replaced the 3 pin mains plug 5A fuse by 1A, mains current = 90mA

Mains transformer primary winding resistance = 58 ohms with 240 volts selected. Noticed that the primary winding wire colours bear little resemblance to the schematic.

Mains transformer secondary supply to the EZ80 full wave rectifier valve anodes = 650V, heater supply to EZ80 = 6.77V, heater supply to amplifier = 6.7V

+HT output at smoothing capacitor C29 (50uF) = +294V, mains 100Hz (10mS) ripple at both C29 & C30 (50uF reservoir) is very high, believe this is due to no real DC current flow due to no load, so expect the ripple to drop a lot when load (amplifier) is connected.
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Old 20th Sep 2020, 11:51 am   #33
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Default Re: Brenell Purchases

Those are Bogen heads and they have a habit of being open circuit. Check the resistance of winding with a digital meter and put a series resistor in circuit so as to limit the current or you may cause then to fail. The round heads in a Mu-metal shield are the original types used on Mk 1 machines and some other earlier decks. Those are 'repairable' but not the Bogens.
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Old 20th Sep 2020, 12:22 pm   #34
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Default Re: Brenell Purchases

Looks like some lack of capacitance or leakage in the PSU.

Lawrence.
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Old 20th Sep 2020, 3:34 pm   #35
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Thank you Lawrence, I am glad you said that. When I started looking at the PSU I had intended to measure the dual can capacitor but completely forgot all about it.

Now have just measured them and they both are very low. The highest reading I can get per can is around 10uF with a pretty high 140 ohms ESR. Another of my capacitance meters reads them as low as 3uF.

The bottom of the can is cracked but no sign of any leakage.

So now to find some replacements, definitely will not have any suitable dual cans but may possibly have suitable radials. It worse comes to worse may have to borrow the can from the Mk.5, although that one being the older unit may not be any good either.

David
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Old 20th Sep 2020, 5:13 pm   #36
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Default Re: Brenell Purchases

You can always get another dual can if you wish: https://www.hotroxuk.com/jj-capacitors-caps.html I'm not sure if you meant at worst you couldn't get hold of one, or that you wouldn't have a spare one knocking around.
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Old 20th Sep 2020, 5:43 pm   #37
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Default Re: Brenell Purchases

Thank you Uncle Bulgaria. Yes I meant I would not have spare one at home, guessed that would be able to buy new, these seem good value. Nowadays I am trying to cut down somewhat on new/NOS components I buy, try and find suitable at home where ever possible.

Have now found some 47uF/350V new radials, will fit 2 of these, finding it a bit awkward to fit them in without fouling other things.

Last edited by DMcMahon; 20th Sep 2020 at 5:48 pm. Reason: Update
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Old 20th Sep 2020, 8:03 pm   #38
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After fitting the new replacement capacitors the AC mains ripple has reduced hugely down to < 50mV.

Of course correspondingly the DC output has ramped up, it s now around 440V, which seems rather large. Hopefully this will come down to a more normal level of < 300V when loaded by the amplifier.
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Old 20th Sep 2020, 9:27 pm   #39
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Default Re: Brenell Purchases

Measured the DC resistance of the Series 2 Bogen heads using a series current limiting resistor (100 ohms).

Erase = 11 ohms (with series resistor value subtracted).
R/P = 214 ohms (with series resistor value subtracted).

Do not know the typical DC resistance values for these heads, but because they are not open circuit, hopefully they should be OK electrically.

DC resistance values stated in the Mk. 5 manual for the original heads (non Bogen) are Erase 0.5 ohm and R/P 60 ohms.
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Old 21st Sep 2020, 11:04 am   #40
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Default Re: Brenell Purchases

Series 2:-

Cleaned off all the black mess off the R/P head, its condition does not look great.

Cleaned the sticky mess off the 4 motor "Dubilier SFK24R" CR suppressor transorbs (0.02uF + 220 ohms), no sign that it leaked out of the suppressors.

Disconnected and measured them. All 4 measured 140 ohms ESR which I assume must be the 220 ohms resistor. Their capacitance was OK ranging from 0.02 to 0.033uF. Their insulation resistance was not great ranging from 750k to 3Mohm at 250 volts.

Measured the capstan motor Run capacitor C81 (2uF), a range of readings from 3 meters, 2.77uF up to 6.2uF. Poor insulation of 250kohm at 250 volts.
Will see how the motor runs, maybe time to replace the capacitor.

Cleaned off a nick/burr on the L2 Pressure Pad arm tape contact release pin.
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