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Reviews Categories | Keyers & CW Keyboards | MFJ-452 Help

Reviews Summary for MFJ-452
MFJ-452 Reviews: 5 Average rating: 3.4/5 MSRP: $149.95
Description: Keyboard keyer
Product is in production.
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W9RAC Rating: 5/5 May 21, 2016 17:17 Send this review to a friend
Works like a charm  Time owned: 0 to 3 months
I purchased this since I had learned to type in high school and Arthritis has been working on me. Makes like easier for me and received end also. BE CERTAIN to check the jumper inside before you start, mine was set for tube type from factory , I wasted a bit of time before I checked.
N3DG3 Rating: 5/5 Feb 3, 2008 08:22 Send this review to a friend
Super & Reliable  Time owned: more than 12 months
I have had several of these MFJ452 CW Keyboards, and have had no problem at all, at any power level. They are compact, loaded with features and indeed, send flawless CW.
W5CPT Rating: 5/5 Jan 25, 2007 15:44 Send this review to a friend
Works for me  Time owned: 6 to 12 months
I bought my 452 used and after reseting the weight correctly (it was set to zero and sent dits for dahs and vice-versa) it has worked flawlessly. It is the only keyboard keyer with 8 memories that I found. It came with a heavy metal frame keyboard but I use a regular plastic one I had in my goody bin. It is easyier to move around on the bench. I have had no RF problems but I have resonant antennas so I think the RF in my shack is minimal.
N5DF Rating: 1/5 Feb 3, 2003 09:23 Send this review to a friend
Do NOT Buy a MFJ-452  Time owned: 3 to 6 months
Do not buy the MFJ-452 CW keyboard.

My MFJ-452 was very sensitive to RFI. It was unstable in that it would reset (reboot) itself at random while I typed on it. I would be typing away, in the middle of a QSO, and wam! The keyboard would reset itself just like you quickly turned the power off then on again. This could happen at random times. Sometimes, I could go for an hour or more without any problem. Other times the board would reset itself very frequently. Once, I was practicing my typing, listening to the keyboard's sidetone but not transmitting (the TX was off). The unit reset itself three times during my practice session that afternoon. While my MFJ-452 was sensitive to RFI, it also had stability problems.

The above mentioned problem was not unique to my unit. In the three months that I had the unit, I QSOed about a half dozen hams who had experience with the MFJ-452. EACH of them said that they too had random reset and/or other problems.

I tried everything reasonable to solve the problem. I ran the unit from batteries. I put a dozen ferrite beads (Type 73 material) on every lead that attached to the unit. I got a PC 101 key keyboard with the (largely-plastic) keyswitch assembly bolted to a large aluminum plate ground plane (the ground plane was attached to both the shield and signal ground in the keyboard cable that attached the PC keyboard to the 452). Furthermore, I used aluminum tape (the wide type that is used to tape-up air conditioning ducts)to further shield the circuit board in the PC keyboard that I used with the 452 (the ground plane and all foil shielding was connected electrically to the cable shield and signal ground wire). All of this seemed to help, but it did not solve the problem.

Also frustrating was the MFJ-452 manual. My MFJ-452 manual contained the schematic diagram for a MFJ-451 and NO schematic for the 452!!! (the 452 contains a LCD display while the 451 does not).

Eventually, I gave up. Since my 452 was still under warranty (MFJ's "No Matter What" warranty), I sent it back to MFJ with a check for $30.00. They sent me their new-to-the-market MFJ-495 Millennium keyer/keyboard.

What a difference! When my new 495 *finally* arrived (you cannot be in a hurry when you are dealing with MFJ Customer Service), I put it on the air and have not had any trouble at all. My MFJ-495 works as advertised, and it is a pleasure to use.

By the way, with the 452, I bought MFJ's "RFI suppressed" PC keyboard unit. I took the PC keyboard switch assembly apart and found that the only RFI suppression was a few ferrite beads on the cable. Otherwise, my MFJ "RFI suppressed" PC keyboard is a fairly standard plastic PC keyboard. I threw the thing in the closet, and I obtained (and further modified/shielded)the PC keyboard that is described above.

My bottom line: Do not buy the MFJ-452 CW keyboard. Buy the MFJ-495 instead.

John, n5df

WA9WJB Rating: 1/5 Jan 19, 2003 18:13 Send this review to a friend
Disappointing.  Time owned: more than 12 months
The MFJ-452 Keyboard keyer is packed with a lot of nice features, but before you run out and buy one, consider this. The unit is overly sensitive to RF pickup and reboots as a result. I think the keyboard picks up RF and sends strange characters or commands to the processor, which sends to unit into reboot. It hung-up one time and I had to take the unit apart and ground one of the pins to the processor for a master reboot.

Also, I am not a perfect typist. I sometimes hit two keys at the same time. On some key combinations when I hit two keys simultaneously, the unit will start sending from another memory location with stored messages, or send something from the current buffer (that was just sent), or send a group of random characters, and won't stop sending until the power is cycled OFF/ON. This effect happens even when the transmitter is OFF, not being used.

Two letters, two Emails, and one phone call to MFJ for help went unanswered. However, I made one last call to MFJ and talked to a guy who was "a little familiar" with the unit, and he told me which pin to ground to reset the processor.

I currently use the MFJ-452 as a beacon sender (CQ repeat, contest calling, generate code practice tapes for Novices, etc), but as a sending unit for real time sending, it is not robust enough to stay out of trouble.



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